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Middle Ages, the period in European history from the collapse of Roman civilization in the 5th century ce to the period of the Renaissance (variously interpreted as beginning in the 13th, 14th, or 15th century, depending on the region of Europe and other factors).

A brief treatment of the Middle Ages follows. For full treatment, see Europe, history of: The Middle Ages.

The term and its conventional meaning were introduced by Italian humanists with invidious intent. The humanists were engaged in a revival of Classical learning and culture, and the notion of a thousand-year period of darkness and ignorance separating them from the ancient Greek and Roman world served to highlight the humanists' own work and ideals. It would seem unnecessary to observe that the men and women who lived during the thousand years or so preceding the Renaissance were not conscious of living in the Middle Ages. A few- Petrarch was the most conspicuous among them-felt that their lot was cast in a dark time, which had begun with the decline of the Roman Empire. Indeed, Petrarch would provide something of a founding statement for the humanists when he wrote, "For who can doubt that Rome would rise again instantly if she began to know herself?"

In a sense, the humanists invented the Middle Ages in order to distinguish themselves from it. They were making a gesture of their sense of freedom, and yet, at the same time, they were implicitly accepting the medieval conception of history as a series of well-defined ages within a limited framework of time. They did not speak of Augustine's Six Ages of the World or believe in the chronology of Joachimite prophecy, but they nevertheless inherited a philosophy of history that began with the Garden of Eden and would end with the Second Coming of Christ. In such a scheme, the thousand years from the 5th to the 15th century might well be regarded as a distinct respectable period of history, which would stand out clearly in the providential pattern. Throughout European history, however, there has never been a complete breach with medieval institutions or modes of thought.

The sack of Rome by Alaric the Visigoth in 410 ce had enormous impact on the political structure and social climate of the Western world, for the Roman Empire had provided the basis of social cohesion for most of Europe. Although the Germanic tribes that forcibly migrated into southern and western Europe in the 5th century were ultimately converted to Christianity, they retained many of their customs and ways of life. The changes in forms of social organization they introduced rendered centralized government and cultural unity impossible. Many of the improvements in the quality of life introduced during the Roman Empire, such as a relatively efficient agriculture, extensive road networks, water-supply systems, and shipping routes, decayed substantially, as did artistic and scholarly endeavours.

This decline persisted throughout the Migration period, a historical period sometimes called the Dark Ages, Late Antiquity, or the Early Middle Ages. The Migration period lasted from the fall of Rome to about the year 1000, with a brief hiatus during the flowering of the Carolingian court established by Charlemagne. Apart from that interlude, no large political structure arose in Europe to provide stability. Two great kingdoms, Germany and Italy, began to lose their political unity almost as soon as they had acquired it; they had to wait until the 19th century before they found it again. The only force capable of providing a basis for social unity was the Roman Catholic Church. The Middle Ages therefore present the confusing and often contradictory picture of a society attempting to structure itself politically on a spiritual basis. This attempt came to a definitive end with the rise of artistic, commercial, and other activities anchored firmly in the secular world in the period just preceding the Renaissance.

After the dissolution of the Roman Empire, the idea arose of Europe as one large church-state, called Christendom. Christendom was thought to consist of two distinct groups of functionaries: the sacerdotium, or ecclesiastical hierarchy, and the imperium, or secular leaders. In theory, these two groups complemented each other, attending to people's spiritual and temporal needs, respectively. Supreme authority was wielded by the pope in the first of these areas and by the emperor in the second. In practice, the two institutions were constantly sparring, disagreeing, or openly warring with each other. The emperors often tried to regulate church activities by claiming the right to appoint church officials and to intervene in doctrinal matters. The church, in turn, not only owned cities and armies but often attempted to regulate affairs of state. This tension would reach a breaking point in the late 11th and early 12th centuries during the clash between Emperor Henry IV and Pope Gregory VII over the question of lay investiture.

During the 12th century a cultural and economic revival took place; many historians trace the origins of the Renaissance to this time. The balance of economic power slowly began to shift from the region of the eastern Mediterranean to western Europe. The Gothic style developed in art and architecture. Towns began to flourish, travel and communication became faster, safer, and easier, and merchant classes began to develop. Agricultural developments were one reason for these developments; during the 12th century the cultivation of beans made a balanced diet available to all social classes for the first time in history. The population therefore rapidly expanded, a factor that eventually led to the breakup of the old feudal structures.

The 13th century was the apex of medieval civilization. The classic formulations of Gothic architecture and sculpture were achieved. Many different kinds of social units proliferated, including guilds, associations, civic councils, and monastic chapters, each eager to obtain some measure of autonomy. The crucial legal concept of representation developed, resulting in the political assembly whose members had plena potestas-full power-to make decisions binding upon the communities that had selected them. Intellectual life, dominated by the Roman Catholic Church, culminated in the philosophical method of Scholasticism, whose preeminent exponent, St. Thomas Aquinas, achieved in his writings on Aristotle and the Church Fathers one of the greatest syntheses in Western intellectual history.

The breakup of feudal structures, the strengthening of city-states in Italy, and the emergence of national monarchies in Spain, France, and England, as well as such cultural developments as the rise of secular education, culminated in the birth of a self-consciously new age with a new spirit, one that looked all the way back to Classical learning for its inspiration and that came to be known as the Renaissance.

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Middle Ages | Definition, Dates, Characteristics, & Facts

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Middle Ages, the period in European history from the collapse of Roman civilization in the 5th century CE to the dawn of the Renaissance (variously interpreted as beginning in the 13th, 14th, or 15th century, depending on the region of Europe and other factors).

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Overview: The Middle Ages, 1154 - 1485

Overview: The Middle Ages, 1154 - 1485

Far from their dour reputation, the Middle Ages were a period of massive social change, burgeoning nationalism, international conflict, terrible natural disaster, climate change, rebellion, resistance and renaissance.

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Turmoil, crisis and the creation of a state, from Magna Carta to the horrors of the Black Death.

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The Middle Ages: Birth of an Idea The phrase "Middle Ages" tells us more about the Renaissance that followed it than it does about the era itself. Starting around the 14th century, European thinkers, writers and artists began to look back and celebrate the art and culture of ancient Greece and Rome. Accordingly, they dismissed [...]
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Middle Ages: Definition and Timeline | HISTORY

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Featured The Middle Ages: Birth of an Idea The phrase "Middle Ages" tells us more about the Renaissance that followed it than it does about the era itself. Starting around the 14th century, European thinkers, writers and artists began to look back and celebrate the art and culture of ancient Greece and Rome.

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The Black Death was a devastating global epidemic of bubonic plague that struck Europe and Asia in the mid-1300s. Explore the facts of the plague, the symptoms it caused and how millions died from it.

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The name the Hundred Years' War has been used by historians since the beginning of the nineteenth century to describe the long conflict that pitted the kings and kingdoms of France and England against each other from 1337 to 1453. Two factors lay at the origin of the conflict: first, the status of the duchy of Guyenne (or Aquitaine)-though it belonged to the kings of England, it remained a fief of the French crown, and the kings of England wanted independent possession; second, as the closest relatives of the last direct Capetian king (Charles IV, who had died in 1328), the kings of England from 1337 claimed the crown of France.

Theoretically, the French kings, possessing the financial and military resources of the most populous and powerful state in western Europe, held the advantage over the smaller, more sparsely populated English kingdom. However, the expeditionary English army, well disciplined and successfully using their longbows to stop cavalry charges, proved repeatedly victorious over much larger French forces: significant victories occurred by sea at Sluys (1340), and by land at Crecy (1346) and Poitiers (1356). In 1360, King John of France, in order to save his title, was forced to accept the Treaty of Calais, which granted complete independence to the duchy of Guyenne, now considerably enlarged to include almost a third of France. However, his son Charles V, with the help of his commander in chief Bertrand du Guesclin, by 1380 had succeeded in reconquering almost all the ceded territory, notably by a series of sieges.

After a hiatus, Henry V of England renewed the war and proved victorious at Agincourt (1415), conquered Normandy (1417-1418), and then attempted to have himself crowned as the future king of France by the Treaty of Troyes (1420). But his military successes were not matched by political successes: although allied with the dukes of Burgundy, the majority of the French refused English domination. Thanks to Joan of Arc, the siege of Orleans was lifted (1429). Then Paris and the lle-de-France were liberated (1436-1441), and after the French army had been reorganized and reformed (1445-1448), Charles VII recaptured the duchy of Normandy (the Battle of Formigny, 1450), and then seized Guyenne (the Battle of Castillon, 1453). The end of the conflict was never marked by a peace treaty but died out because the English recognized that the French troops were too strong to be directly confronted.

English territory in France, which had been extensive since 1066 (see Hastings, Battle of) now remained confined to the Channel port of Calais (lost in 1558). France, at last free of the English invaders, resumed its place as the dominant state of western Europe.

The Reader's Companion to Military History. Edited by Robert Cowley and Geoffrey Parker. Copyright © 1996 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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The name the Hundred Years' War has been used by historians since the beginning of the nineteenth century to describe the long conflict that pitted the kings and kingdoms of France and England against each other from 1337 to 1453.

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BBC Documentary | National Geographic History Channel

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National Geographic Documentary HD   History Channel   The Library of Alexandria Documentary

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Uploaded by Documentaries Channel on 2016-01-16.

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Dark ages

In September 476 AD, the last Roman emperor of the west, Romulus Augustulus, was deposed by a Germanic prince called Odovacar, who had won control of the remnants of the Roman army of Italy. He then sent the western imperial regalia to Constantinople.

The Roman empire in western Europe - a centralised superstate which had been in existence for 500 years - had ceased to exist, its single emperor replaced by upwards of a dozen kings and princes.

The vast majority of these rulers, like Odovacar himself , were non-Roman in origin. Their power was based on the control of military forces which were the direct descendents of recent immigrants into the Roman world, whether Anglo-Saxons in Britain, Goths in southern Gaul and Spain, or Vandals in North Africa.

What difference did this political revolution make to real life in the former western Empire?

For many 19th and earler 20th century commentators, the fall of Rome marked the death knell of education and literacy, sophisticated architecture, advanced economic interaction, and, not least, the rule of written law.

The 'dark ages' which followed were dark not only because written sources were few and far between, but because life became nasty, brutish and short.

Other commentators, who were more focused on the slavery and entrenched social hierarchies that were also part of the Roman world, didn't really disagree with these observations.

But they saw the 'dark ages' as a more necessary evil - Rome had to fall to destroy large-scale slavery and make possible, eventually, a world which valued all human beings more equally.

On either view, the end of empire was a major event in human history.

Massive inequality

The 1960s, however, were famously a time when all established certainties were challenged, and this applied to ancient history no less than to sexuality.

The eastern half of the Roman empire not only survived the collapse of its western partner in the third quarter of the fifth century, but went on to thrive in the sixth.

Under Justinian I (527 - 565 AD), it was still constructing hugely impressive public monuments, such as the Hagia Sophia in Constantinople, and had reconquered Italy, North Africa, and parts of Spain.

At the same time, there still lived in the west many individuals, who continued to describe themselves as Romans, and many of the successor states, it was correctly pointed out, were still operating using recognisably Roman institutions and justifying themselves ideologically with reference to canonical Roman values.

Consequently, by the late 1990s the word 'transformation' had come into vogue. No one denied that many things changed between 350 and 600 AD, but it became fashionable to see these changes as much more the result of long-term evolution than of a violent imperial collapse.

These revisionist arguments have some real substance. There really was little change at one deep level - the life of the peasant producers who made up perhaps 90% of the population.

I am still staggered by feats of Roman engineering, blown away by the beauty of some the buildings Romans lived in, and delighted by the sophistication of the empire's literary and political culture.

But these cultural glories were limited to a tiny privileged elite - those who owned enough land to count as gentry landowners. They represented maybe 3% of the whole population. Its structures were probably unspeakable vile to pretty much everyone else.

As late as 383 AD, captive barbarians were being fed to wild animals in the Colosseum, and its criminal law dealt ruthlessly with anyone seeking to remedy the highly unequal distribution of property.

In 650 AD, as in 350 AD, peasants were still labouring away in the much the same way to feed themselves and to produce the surplus which funded everything else.

Roman culture

In judging these effects, it is important to recognise two separate dimensions of 'Roman-ness' - 'Roman' in the sense of the central state, and 'Roman' in the sense of characteristic patterns of life prevailing within its borders.

At the state level, the empire was not just replaced by mini versions of itself, even where Roman landowners survived. Within two generations of 476 AD, a new and weaker type of state structure had emerged right across the former Roman west.

The old empire had employed two key levers of central power - large-scale taxation, two-thirds of which was then spent on maintaining the second lever, a large professional army.

This high-tax, high-spend structure meant that the Roman state both intruded itself bureaucratically into localities to raise taxation, and was also able, if necessary, to compel obedience to its demands by employing the army, which the taxation supported.

The new states of post-Roman Europe were much weaker affairs. Even where other less important Roman institutions survived, the new kings had only much-diminished revenue rights and their armies were composed of semi-professional contingents of local landowners.

On the level of local 'Roman-ness' too, the revolution could not have been more profound. The characteristic patterns of local Roman life were in fact intimately linked to the existence of the central Roman state, and, as the nature of state structures changed in the post-Roman world, so too did local life.

The Roman city, for instance, was the basic unit of local administration through which taxation was raised. As central tax raising powers disappeared, so too did the need to keep the city, and by 700 AD it was history.

Many of the more advanced elements of the Roman economy, such as specialised production and long-distance trade, quickly disappeared too.

The Roman state had subsidised large-scale transport structures for its own purposes, but these had also been used by traders. As this command economy collapsed, so did much of the trade dependent upon it.

Cultural patterns were also transformed beyond recognition. Roman elites learned to read and write classical Latin to highly-advanced levels through a lengthy and expensive private education, because it qualified them for careers in the extensive Roman bureaucracy.

The end of taxation meant that these careers disappeared in the post-Roman west, and elite parents quickly realised that spending so much money on learning Latin was now a waste of time. As a result, advanced literacy was confined to churchmen for the next 500 years.

Militarisation

Everywhere you look, the fall of the Rome let loose profound change. At the heart of it all, where change at state and local level intertwined, lay the militarisation of elite landowners.

The end of the Roman empire generated many states where previously there had been one, and another casualty of 476 AD was thus the Pax Romana. Warfare became endemic to the former Roman west.

In this situation, successor state kings needed military service above all, and quickly mobilised Roman landowners with contingents of their retainers to fight alongside the descendents of their migrant warbands.

But taxation had always been justified in the Roman period by the fact that it paid for defence. When successor state kings made local Roman landowners turn out for battle, not only was it a nasty shock, but it was also the ultimate double whammy.

Having to pay taxation and fight was massively unpopular - witness the stringing up of the Roman grandee Parthenius, employed by the Frankish king Chilperic as his chief tax collector in 574 AD. Kings quickly realised that they could gain much popularity by canceling tax obligations.

In the short term, they could do so since they no longer needed the money for a professional army. But in the longer term, it was precisely this process which created the new Europe of powerful local landowners and relatively powerless states, which lacked both tax revenues and professional armies, and generated the cultural change, since literacy was now so marginal to secular elite life.

It also brings us back to the peasantry. One striking feature of post-Roman archaeology is the substantial decline it demonstrates in overall population. Even if peasants don't fight, they are not immune to the effects of warfare, and declining economic opportunity also hit their capacities to make a living. Though probably not really aware of it, they too had benefited from the Pax Romana.

Dark age Europe was born out of the violent destruction of the Roman empire, as the battlefield replaced the bureau at the heart of elite life, but its ramifications were felt at every social level.

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In September 476 AD, the last Roman emperor of the west, Romulus Augustulus, was deposed by a Germanic prince called Odovacar, who had won control of the remnants of the Roman army of Italy. He then sent the western imperial regalia to Constantinople.

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To many historians, the fall of the Western Roman Empire in the 5th century CE has always been viewed as the end of the ancient world and the onset of the Middle Ages, often improperly called the Dark Ages, despite Petrarch's assertion. Since much of the west had already fallen by the middle of the 5th century CE, when a writer speaks of the fall of the empire, he or she generally refers to the fall of the city of Rome. Although historians generally agree on the year of the fall, 476 CE, they often disagree on its causes. English historian Edward Gibbon, who wrote in the late 18th century CE, points to the rise of Christianity and its effect on the Roman psyche while others believe the decline and fall were due, in part, to the influx of 'barbarians' from the north and west.

Whatever the cause, whether it was religion, external attack, or the internal decay of the city itself, the debate continues to the present day; however, one significant point must be established before a discussion of the roots of the fall can continue: the decline and fall were only in the west. The eastern half - that which would eventually be called the Byzantine Empire - would continue for several centuries, and, in many ways, it retained a unique Roman identity.

External CAuses

One of most widely accepted causes - the influx of a barbaric horde - is discounted by some who feel that mighty Rome, the eternal city, could not have so easily fallen victim to a culture that possessed little or nothing in the way of a political, social or economic foundation. They believe the fall of Rome simply came because the barbarians took advantage of difficulties already existing in Rome - problems that included a decaying city (both physically and morally), little to no tax revenue, overpopulation, poor leadership, and, most importantly, inadequate defense. To some the fall was inevitable.

Unlike the fall of earlier empires such as the Assyrian & Persian, Rome did not succumb to either war or revolution.

Unlike the fall of earlier empires such as the Assyrian and Persian, Rome did not succumb to either war or revolution. On the last day of the empire, a barbarian member of the Germanic tribe Siri and former commander in the Roman army entered the city unopposed. The one-time military and financial power of the Mediterranean was unable to resist. Odovacar easily dethroned the sixteen-year-old emperor Romulus Augustalus, a person he viewed as posing no threat. Romulus had recently been named emperor by his father, the Roman commander Orestes, who had overthrown the western emperor Julius Nepos. With his entrance into the city, Odovacar became the head of the only part that remained of the once great west: the peninsula of Italy. By the time he entered the city, the Roman control of Britain, Spain, Gaul, and North Africa had already been lost to the Goths and Vandals. Odovacar immediately contacted the eastern emperor Zeno and informed him that he would not accept that title of emperor. Zeno could do little but accept this decision. In fact, to ensure there would be no confusion, Odovacar returned to Constantinople the imperial vestments, diadem, and purple cloak of the emperor.

Internal causes

There are some who believe, like Gibbon, that the fall was due to the fabric of the Roman citizen. If one accepts the idea that the cause of the fall was due, in part, to the possible moral decay of the city, its fall is reminiscent of the "decline" of the Republic centuries earlier. Historian Polybius, a 2nd century BCE writer, pointed to a dying republic (years before it actually fell) - a victim of its declining moral virtue and the rise of vice within. Edward Gibbon reiterated this sentiment (he diminished the importance of the barbaric threat) when he claimed the rise of Christianity as a factor in the "tale of woe" for the empire. He held the religion sowed internal division and encouraged a "turn-the-other-cheek mentality" which ultimately condemned the war machine, leaving it in the hands of the invading barbarians. Those who discount Gibbon's claim point to the existence of the same religious zealots in the east and the fact that many of the barbarians were Christian themselves.

To Gibbon the Christian religion valued idle and unproductive people. Gibbon wrote in his book The History of Decline and Fall of the Roman Empire,

A candid but rational inquiry into the progress and establishment of Christianity, may be considered as a very essential part of the history of the Roman empire. While this great body was invaded by open violence, or undermined by slow decay, a pure and humble religion greatly insinuated itself into the minds of men, grew up in silence and obscurity, derived new vigour from opposition, and finally erected the triumphant banner of the cross on the ruins of the Capitol."

He added that the Roman government appeared to be "odious and oppressive to its subjects" and therefore no serious threat to the barbarians.

Gibbon, however, does not single out Christianity as the only culprit. It was only one in a series that brought the empire to its knees. In the end, the fall was inevitable:

...the decline of Rome was the natural and inevitable effect of immoderate greatness. Prosperity ripened the principle of decay; the causes of destruction multiplied with the extent of conquest, and as soon as time or accident has removed artificial supports, the stupendous fabric yielded to the pressure of its own weight.

A Divided Empire

Although Gibbon points to the rise of Christianity as a fundamental cause, the actual fall or decline could be seen decades earlier. By the 3rd century CE, the city of Rome was no longer the center of the empire - an empire that extended from the British Isles to the Tigris and Euphrates Rivers and into Africa. This massive size presented a problem and called for a quick solution, and it came with the reign of Emperor Diocletian. The empire was divided into two with one capital remaining at Rome and another in the east at Nicomedia; the eastern capital would later be moved to Constantinople, old Byzantium, by Emperor Constantine. The Senate, long-serving in an advisory capacity to the emperor, would be mostly ignored; instead, the power centered on a strong military. Some emperors would never step foot in Rome. In time Constantinople, Nova Roma or New Rome, would become the economic and cultural center that had once been Rome.

Despite the renewed strength that the division provided (the empire would be divided and united several times), the empire remained vulnerable to attack, especially on the Danube-Rhine border to the north. The presence of barbarians along the northern border of the empire was nothing new and had existed for years - the army had met with them on and off since the time of Julius Caesar. Some emperors had tried to buy them off, while others invited them to settle on Roman land and even join the army. However, many of these new settlers never truly became Roman even after citizenship was granted, retaining much of their old culture.

Roman vulnerability became more obvious as a significant number of Germanic tribes, the Goths, gathered along the northern border.

This vulnerability became more obvious as a significant number of Germanic tribes, the Goths, gathered along the northern border. They did not want to invade; they wanted to be part of the empire, not its conqueror. The empire's great wealth was a draw to this diverse population. They sought a better life, and despite their numbers, they appeared to be no immediate threat, at first. However, as Rome failed to act to their requests, tensions grew. This anxiety on the part of the Goths was due to a new menace further to the east, the Huns.

The Goth Invasion

During the reign of the eastern emperor Valens (364 -378 CE), the Thervingi Goths had congregated along the Danube-Rhine border - again, not as a threat, but with a desire only to receive permission to settle. This request was made in urgency, for the "savage" Huns threatened their homeland. Emperor Valens panicked and delayed an answer - a delay that brought increased concern among the Goths as winter was approaching. In anger, the Goths crossed the river with or without permission, and when a Roman commander planned an ambush, war soon followed. It was a war that would last for five years.

Although the Goths were mostly Christian many who joined them were not. Their presence had caused a substantial crisis for the emperor; he couldn't provide sufficient food and housing. This impatience, combined with the corruption and extortion by several Roman commanders, complicated matters. Valens prayed for help from the west. Unfortunately, in battle, the Romans were completely outmatched and ill-prepared, and the Battle of Adrianople proved this when two-thirds of the Roman army was killed. This death toll included the emperor himself. It would take Emperor Theodosius to bring peace.

An Enemy from within: Alaric

The Goths remained on Roman land and would ally themselves with the Roman army. Later, however, one man, a Goth and former Roman commander, rose up against Rome - a man who only asked for what had been promised him - a man who would do what no other had done for eight centuries: sack Rome. His name was Alaric, and while he was a Goth, he had also been trained in the Roman army. He was intelligent, Christian, and very determined. He sought land in the Balkans for his people, land that they had been promised. Later, as the western emperor delayed his response, Alaric increased his demands, not only grain for his people but also recognition as citizens of the empire; however, the emperor, Honorius, continually refused. With no other course, Alaric gathered together an army of Goths, Huns and freed slaves and crossed the Alps into Italy. His army was well-organized, not a mob. Honorius was incompetent and completely out of touch, another in a long line of so-called "shadow emperors" - emperors who ruled in the shadow of the military. Oddly enough, he didn't even live in Rome but had a villa in nearby Ravenna.

Alaric sat outside the city, and over time, as the food and water in the city became increasingly scarce, Rome began to weaken. The time was now. While he had never wanted war but only land and recognition for his people Alaric, with the supposed help of a Gothic slave who opened the gates from within, entered Rome in August of 410 CE. He would stay for three days and completely sack the city; although he would leave St. Paul and St Peters alone. Honorius remained totally blind to the seriousness of the situation. While temporarily agreeing to Alaric's demands - something he never intended to honor - 6,000 Roman soldiers were sent to defend the city, but they were quickly defeated. Even though the city's coffers were nearly empty, the Senate finally relinquished; Alaric left with, among other items, two tons of gold and thirteen tons of silver.

Some people at the time viewed the sacking of the city as a sign from their pagan gods. St. Augustine, who died in 430 CE, said in his City of God that the fall of Rome was not a result of the people's abandonment of their pagan gods (gods they believed protected the city) but as a reminder to the city's Christians why they needed to suffer. There was good, for the world was created by good, but it was flawed by human sin; however, he still believed the empire was a force for peace and unity. To St. Augustine there existed two cities: one of this world and one of God.

Barbarian Invasions

Although Alaric would soon die afterwards, other barbarians - whether Christian or not - did not stop after the sack of the city. The old empire was ravaged, among others, by Burgundians, Angles, Saxons, Lombards, and Magyars. By 475 CE Spain, Britain, and parts of Gaul had been lost to various Germanic people and only Italy remained as the "empire" in the west. The Vandals would soon move from Spain and into northern Africa, eventually capturing the city of Carthage. The Roman army abandoned all hope of recovering the area and moved out. The loss of Africa meant a loss of revenue, and the loss of revenue meant there was less money to support an army to defend the city. Despite these considerable losses, there was some success for the Romans. The threat from Attila the Hun was finally stopped at the Battle of Chalons by Roman commander Aelius who had created an army of Goths, Franks, Celts and Burgundians. Even Gibbon recognized Attila as one "who urged the rapid downfall of the Roman empire." While Attila would recover and sack several Italian cities, he and the Hun threat ended with his death due to a nosebleed on his wedding night.

The loss of revenue for the western half of the empire could not support an army capable of defending the already vulnerable borders.

Conclusion: Multiple Factors

One could make a sound case for a multitude of reasons for the fall of Rome. However, its fall was not due to one cause, although many search for one. Most of the causes, initially, point to one place: the city of Rome itself. The loss of revenue for the western half of the empire could not support an army - an army that was necessary for defending the already vulnerable borders. Continual warfare meant trade was disrupted; invading armies caused crops to be laid to waste, poor technology made for low food production, the city was overcrowded, unemployment was high, and lastly, there were always the epidemics. Added to these was an inept and untrustworthy government.

The presence of the barbarians in and around the empire added to a crisis not only externally but internally. These factors helped bring an empire from "a state of health into non-existence." The Roman army lacked both proper training and equipment. The government itself was unstable. Peter Heather in his The Fall of the Roman Empire states that it "fell not because of its 'stupendous fabric' but because its German neighbors responded to its power in ways that the Romans could not ever have foreseen... By virtue of its unbounded aggression, Roman imperialism was responsible for its own destruction."

Rome's fall ended the ancient world and the Middle Ages were borne. These "Dark Ages" brought the end to much that was Roman. The West fell into turmoil. However, while much was lost, western civilization still owes a debt to the Romans. Although only a few today can speak Latin, it is part of our language and the foundation of the Romance languages of French, Italian, and Spanish. Our legal system is based on Roman law. Many present day European cities were founded by Rome. Our knowledge of Greece comes though Rome and many other lasting effects besides. Rome had fallen but it had been for so so long one of the history's truly world cities.

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To many historians, the fall of the Western Roman Empire in the 5th century CE has always been viewed as the end of the ancient world and the onset of the Middle Ages, often improperly called the Dark Ages, despite Petrarch's assertion.

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Ancient Discoveries   Robotics  Heron of Alexandria Documentary

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The steam engine facilitated major advancements in the fields of mining, manufacturing, agriculture and transportation.

Credit: Baptist | Shutterstock

In a world propelled by combustion engines, gas turbines and nuclear reactors, the steam engine may seem like a relic of the past. But without this game-changing invention, the modern world would be a much different place.

Arguably the most important development of the Industrial Revolution, the steam engine facilitated major advancements in the fields of mining, manufacturing, agriculture and transportation. And while several prominent figures of the 18th and 19th centuries are credited with developing and improving the steam engine, the history of steam-powered machines actually goes back nearly 2,000 years before the Industrial Revolution.

Early in the first century A.D., a Greek inventor named Hero of Alexandria designed the world's first aeolipile, or primitive steam turbine. Heron's aeolipile consisted of a hollow sphere, mounted on a pair of tubes. Heated from below by fire, the tubes transported steam to the sphere, where it was released through another series of tubes projecting from the sphere's equator. This movement of steam through the device caused the sphere to revolve, demonstrating the potential for using steam as a means of propulsion.

While Hero's aeolipile was created as a novelty, not a means of speeding up production, it is nevertheless the first known device to transform steam into rotary motion. But it wasn't until the 17th century that attempts were made to harness the power exhibited by Heron's aeolipile for practical purposes.

In the first century A.D., Hero of Alexandria invented the aeolipile, or primitive steam turbine.

Credit: Public domain.

The first practical steam engines were developed to solve a very specific problem: how to remove water from flooded mines. As Europeans of the 17th century switched from wood to coal as their main source of fuel, mines were deepened and, as a result, often became flooded after penetrating underground water sources.

A Spanish mining administrator named Jerónimo de Ayanz is thought to have been the first person to solve the problem of flooded mines. In 1606, de Ayanz registered the first patent for a machine that used steam power to propel water from mines. The Spanish inventor - who is also credited with inventing one of the world's first air conditioning systems - used his steam engine to remove water from silver mines in Guadalcanal, Seville.

While the Spaniard first patented a steam-operated machine for use in mining, an Englishman is usually credited with inventing the first steam engine. In 1698, Thomas Savery, an engineer and inventor, patented a machine that could effectively draw water from flooded mines using steam pressure. Savery used principles set forth by Denis Papin, a French-born British physicist who invented the pressure cooker. Papin's ideas surrounding a cylinder and piston steam engine had not previously been used to build a working engine, but by 1705, Savery had turned Papin's ideas into a useful invention.

Using two steam boilers, Savery devised a nearly continuous system for pumping water from mines. But despite the early success of Savery's system, it was soon discovered that his engine was only capable of drawing water from shallow depths, a problem that needed to be overcome if steam engines were to function in deep mines.

Luckily for European mine owners, in 1711 another Englishman, Thomas Newcomen, developed a better way to pump water from mines. His system used a redesigned steam engine that eliminated the need for accumulated steam pressure - a flaw in Savery's system that led to many an unfortunate explosion. Newcomen's "atmospheric" engine - so named because the level of steam pressure it used neared atmospheric pressure - was the first commercially successful machine that used steam to operate a water pump.

Despite it's being an improvement on Savery's initial rendering of the steam engine, Newcomen's atmospheric engine also had its flaws. The machine was highly inefficient, requiring a constant flow of cold water to cool the all-important steam cylinder (the part of the engine where steam pressure is converted into motion), as well as a constant energy source to reheat the cylinder.

Regardless of this major drawback, Newcomen's engine design went unchallenged for the next 50-or-so years and, aside from pumping out mines, was also used to drain wetlands, supply water to towns and even power factories and mills by pumping water from below a water wheel to above it for re-use.

In 1698, Thomas Savery patented a machine that could effectively draw water from flooded mines using steam pressure.

Credit: Public domain.

But by 1765, the fate of Newcomen's engine was sealed. In that year, James Watt, a Scottish instrument maker employed by Glasgow University, began repairing a small model of a Newcomen engine. Watt was perplexed by the large amount of steam consumed by Newcomen's machine and realized that to remedy this inefficiency, he would have to do away with the constant cooling and reheating of the steam cylinder.

To do this, Watt developed a separate condenser, which allowed the steam cylinder to be maintained at a constant temperature and dramatically improved the functionality of Newcomen's engine.

For financial reasons, Watt wasn't immediately able to manufacture his new and improved atmospheric engine. But by 1776, he had formed a partnership with Matthew Boulton, an English manufacturer and engineer dead-set on using steam engines for more than just pumping water from mines.

With financial backing from Boulton, Watt developed a single-acting (and later, a double-acting) rotative steam engine that, along with Watt's signature separate condenser, featured a parallel motion mechanism that doubled the power of the existing steam cylinder. The Boulton-Watt engine was also the first that allowed the machine's operator to control the engine speed with a device called a centrifugal governor. The improved engine used a new gear system - developed by Boulton and Watts' employee, William Murdoch - known as sun and planet gearing, to convert reciprocating (linear) motion into rotative motion.

Watt's improvements to the steam engine, combined with Boulton's vision of a nation powered by steam, facilitated the rapid adoption of steam engines across the United Kingdom and, eventually, the United States. By the 1800s, steam engines were powering mills, factories, breweries and a host of other manufacturing operations. In 1852, the first flight of a steam-powered airship took place. Future iterations of the steam engine also came to define travel, as trains, boats and railways adopted the technology to propel passengers into the 20th century. [See also: How the Steam Engine Changed the World]

Follow Elizabeth Palermo on Twitter @techEpalermo, Facebook or Google+. Follow LiveScience @livescience. We're also on Facebook & Google+.

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In a world propelled by combustion engines, gas turbines and nuclear reactors, the steam engine may seem like a relic of the past. But without this game-changing invention, the modern world would be a much different place. Arguably the most important development of the Industrial Revolution, the steam engine facilitated major advancements in the fields of mining, manufacturing, agriculture and transportation.

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Heron of Alexandria, also called Hero, (flourished c. ad 62, Alexandria, Egypt), Greek geometer and inventor whose writings preserved for posterity a knowledge of the mathematics and engineering of Babylonia, ancient Egypt, and the Greco-Roman world.

Heron's most important geometric work, √ Metrica, was lost until 1896. It is a compendium, in three books, of geometric rules and formulas that Heron gathered from a variety of sources, some of them going back to ancient Babylon, on areas and volumes of plane and solid figures. Book I enumerates means of finding the area of various plane figures and the surface areas of common solids. Included is a derivation of Heron's formula (actually, Archimedes' formula) for the area A of a triangle, A = s( s− a)( s− b)( s− c) in which a, b, and c are the lengths of the sides of the triangle, and s is one-half the triangle's perimeter. Book I also contains an iterative method known by the Babylonians (c. 2000 bc) for approximating the square root of a number to arbitrary accuracy. (A variation on such an iterative method is frequently employed by computers today.) Book II gives methods for computing volumes of various solids, including the five regular Platonic solids. Book III treats the division of various plane and solid figures into parts according to some given ratio.

Other works on geometry ascribed to Heron are Geometrica, Stereometrica, Mensurae, Geodaesia, Definitiones, and Liber Geëponicus, which contain problems similar to those in the Metrica. However, the first three are certainly not by Heron in their present form, and the sixth consists largely of extracts from the first. Akin to these works is the Dioptra, a book on land surveying; it contains a description of the diopter, a surveying instrument used for the same purposes as the modern theodolite. The treatise also contains applications of the diopter to measuring celestial distances and describes a method for finding the distance between Alexandria and Rome from the difference between local times at which a lunar eclipse would be observed at the two cities. It ends with the description of an odometer for measuring the distance a wagon or cart travels. Catoptrica ("Reflection") exists only as a Latin translation of a work formerly thought to be a fragment of Ptolemy's Optica. In Catoptrica Heron explains the rectilinear propagation of light and the law of reflection.

Of Heron's writings on mechanics, all that remain in Greek are Pneumatica, Automatopoietica, Belopoeica, and Cheirobalistra. The Pneumatica, in two books, describes a menagerie of mechanical devices, or "toys": singing birds, puppets, coin-operated machines, a fire engine, a water organ, and his most famous invention, the aeolipile, the first steam-powered engine. This last device consists of a sphere mounted on a boiler by an axial shaft with two canted nozzles that produce a rotary motion as steam escapes. (See the animation.) The Belopoeica ("Engines of War") purports to be based on a work by Ctesibius of Alexandria (fl. c. 270 bc). Heron's Mechanica, in three books, survives only in an Arabic translation, somewhat altered. This work is cited by Pappus of Alexandria (fl. ad 300), as is also the Baroulcus ("Methods of Lifting Heavy Weights"). Mechanica, which is closely based on the work of Archimedes, presents a wide range of engineering principles, including a theory of motion, a theory of the balance, methods of lifting and transporting heavy objects with mechanical devices, and how to calculate the centre of gravity for various simple shapes. Both Belopoeica and Mechanica contain Heron's solution of the problem of two mean proportionals-two quantities, x and y, that satisfy the ratios a: x = x: y = y: b, in which a and b are known-which can be used to solve the problem of constructing a cube with double the volume of a given cube. (For the discovery of the mean proportional relationship see Hippocrates of Chios.)

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Only fragments of other treatises by Heron remain. One on water clocks is referred to by Pappus and the philosopher Proclus (ad 410-485). Another, a commentary on Euclid's Elements, is often quoted in a surviving Arabic work by Abu'l-'Abbās al-Faḍl ibn Ḥātim al-Nayrīzī (c. 865-922).

Learn More in these related Britannica articles:

flourished

62 -

notable works

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Heron of Alexandria | Greek mathematician

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Heron of Alexandria, Greek geometer and inventor whose writings preserved for posterity a knowledge of the mathematics and engineering of Babylonia, ancient Egypt, and the Greco-Roman world. Heron's most important geometric work, Metrica, was lost until 1896. It is a compendium, in three books, of

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Little remains today of the writings of the archaic Greek poet Sappho (fl. late 7th and early 6th centuries B.C.E.), whose work is said to have filled nine papyrus rolls in the great library at Alexandria some 500 years after her death.

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Eratosthenes (276-195 BCE) was an ancient Greek Alexandrian scholar, native of Cyrene, who attained distinction in many fields including philosophy, mathematics, astronomy and history. However, it was in geography where he proved to be more skillful for he was one of the greatest of all ancient geographers. Eratosthenes was also known as Beta: his erudition in many disciplines was remarkable but he often ranked second in all of them. It seems this nickname was chosen by those who disliked him, since Eratosthenes eventually proved that he was one step ahead of his contemporaries in several important areas of learning.

He was friends with Archimedes and the two exchanged ideas, enlarging each others knowledge. In fact, one of the surviving works of Archimedes, The Method, explained to Eratosthenes how mechanical experiments can help the understanding of geometry and this work also helped to encourage experimental methods in Eratosthenes. We can also see here the difference in approach between ancient and modern science. Ancient science used experimentation to help theoretical understanding while modern science uses theory to pursue practical results.

Historical Context

Around Eratosthenes' time the Greek cities of Egypt and the East were flourishing both materially and culturally and most of them were at their peak. Greek was firmly established as a common tongue as was cultural unity along most of the Mediterranean, especially in the eastern-Mediterranean. Every educated person was familiar with Greek and it was widely used as the medium in diplomacy, literature and science, therefore, a book written in Greek could not only be understood by native Greek speakers but also by virtually every educated non-Greek in Egypt and even the Near East.

By the age of 40, Eratosthenes' varied knowledge was so highly regarded that Ptolemy III offered him the role of director of the Alexandrian Library.

As a result of a very large Greek speaking audience, thousands of writers wrote hundreds of thousands of books and their number skyrocketed. Therefore, libraries, having existed in the past in Egypt and Mesopotamia mainly as a luxury, soon became a necessity. Ptolemy I, about 290 BCE, established the Museum and, as part of the Museum, the famous Library of Alexandria which ended up overshadowing the Museum in importance and interest, turning into a major centre of scholarship and research.

Books were considered so important that Ptolemy III ordered that every book brought to Alexandria should be deposited in the Library, the owner of the book should receive a copy of it while the Library kept the original. Government officials inspected every ship that arrived to Alexandria looking for books. He also borrowed from Athens many important manuscripts and gave the Athenians a large security deposit for their return. He finally sent back copies to Athens, the Library retained the originals and he told the Athenians they could keep the money as a fine. This ambition for old books became so intense that the art of dyeing and spoiling new manuscripts to sell them as antiquities to collectors of first editions turned out to be a risky but very profitable activity.

Eratosthenes' Works

His numerous works included various topics. Chronographia sought to accurately determine the dates of the major events in Mediterranean history. In this work he calculated the date of the siege of Troy at 1184 BCE, on the basis of traditional chronologies by the geographer-historian Hecateus. In Geographica he put together many reports from different travellers and explorers in order to describe the physical features of each region and he also explained them through the action of natural phenomena such as water, fire, earthquakes and volcanic eruptions. This work included the accounts of some the most prominent explorers in ancient Greece, including Pytheas of Massalia, who sailed around Scotland to Norway, and possibly to the Arctic Circle about 320 BCE. But it was his essay named On the Measurement of the Earth which challenged his Beta nickname and clearly proved Eratosthenes was number one at combining theory with experimentation in order to produce the most accurate results possible at that time.

Measuring the Earth

By the age of forty, Eratosthenes' varied knowledge was so highly regarded that Ptolemy III offered him the role of director of the Alexandrian Library, one of the most important positions which included the obligation of tutoring the crown prince. It was probably here where he read that in Syene (modern Aswan, Egypt), a city located due south of Alexandria, during the summer solstice (June 21st) something curious took place: the shadows of all objects would grow shorter as noon approached and finally, during noon, temple columns would cast no shadow and the sun would shine directly overhead. Deep wells, which at any other time of the year would remain in shadow, would have the sun shining directly down into them. He noticed that in Alexandria, during that same moment, objects would clearly cast a shadow. This account was surely read by many others, but nobody seemed to think it had any particular importance. Eratosthenes, as impossible as it may sound, saw in this report an opportunity to calculate the circumference of the Earth. It occurred to him he could do so by measuring the length of the shadow of the sun in Alexandria at the time when there was no shadow in Syene. On June 21st at noon, he measured the shadow of an obelisk in Alexandria and by simple geometry he calculated that the sun was 7° 14' from overhead.

It is because the surface of the Earth is curved that at the same time there would be no shadow in Syene and a clear shadow in Alexandria. Moreover, the greater the curvature, the bigger the difference in the length of the shadows. The sun is so far away from us that its rays are parallel when they reach the Earth: objects at different angles to the sun's rays would cast shadows of different lengths. Eratosthenes, based on the observed differences in the shadows' lengths, came to the conclusion that the distance between Alexandria and Syene had to be 7° 14' along the surface of the Earth. In other words, if we imagined one obelisk in Alexandria and another obelisk in Syene extending all the way down to the centre of the Earth, they would there intersect at an angle of 7° 14'. Since a full circle has 360°, 7° 14' is roughly one-fiftieth of the total circumference. Thus, the total circumference of the Earth was fifty times the distance from Alexandria to Syene.

The next step then was to find out the distance between Alexandria and Syene. There are different versions on how Eratosthenes attained this goal. Some say that travellers' reports indicated that camels needed 50 days to cover the trip from Alexandria to Syene and that a camel travelled 100 stadia a day. Others say that Eratosthenes hired a man to go from Alexandria to Syene counting the steps needed to complete the trip. What we know for sure is that he estimated the distance to be 5,000 stadia. We do not know exactly about the conversion of stadia into modern measures, but the general concensus is that 5,000 stadia would be around 800 kilometres. Eratosthenes therefore calculated the total circumference of the Earth to be 40,000 kilometres (250,000 stadia).

Eratosthenes' calculation is about 15% too high, but the accuracy of his figure for the circumference of the Earth would not be equalled until modern times. His method was valid from a theoretical perspective, his measurements of angles were highly accurate but it was his measurement of distance that lacked precision. If he had had an accurate figure for the distance between Alexandria and Syene, his conclusion would have been almost the same as our modern estimations.

Mapping the Earth

Eratosthenes also came up with a technique for charting the Earth's surface. He separated the world known to him into a Northern and Southern division using an east-west line parallel to the equator running through the island of Rhodes and bisecting the Mediterranean. He added a second north-south line at right angles running through Alexandria. Eratosthenes drew additional east-west and north-south lines to his map, but instead of adding these lines in regular intervals, he drew them through famous places: Meroë (the capital of the ancient Ethiopian kings), the Pillars of Hercules, Sicily, the Euphrates River, the mouth of the Indus River and the tip of the Indian peninsula.

The result was an irregular network that served human convenience. For the purpose of giving directions, a regular network would have been more useful, surely Eratosthenes was aware of this. But unfortunately in his day places were located by travellers' reports and oral tradition and this was not good enough to determine sufficient accurate points of reference to draw a regular network. It was Hipparchus of Nicea who later on took the next step and developed a neat regular grid that would provide the means to locate any place by following a simple set of coordinates. Nevertheless, Eratosthenes had certainly proved in his work that theory, observation and experimentation were a powerful and successful combination in the pursuit of knowledge.

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Eratosthenes (276-195 BCE) was an ancient Greek Alexandrian scholar, native of Cyrene, who attained distinction in many fields including philosophy, mathematics, astronomy and history. However, it was in geography where he proved to be more skillful for he was one of the greatest of all ancient geographers.

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guy who starved himself b/c he went blind

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Eratosthenes was born in Cyrene which is now in Libya in North Africa. His teachers included the scholar Lysanias of Cyrene and the philosopher Ariston of Chios who had studied under Zeno, the founder of the school of philosophy. Eratosthenes also studied under the poet and scholar Callimachus who had also been born in Cyrene. Eratosthenes then spent some years studying in Athens.
The library at Alexandria was planned by Ptolemy I Soter and the project came to fruition under his son Ptolemy II Philadelphus. The library was based on copies of the works in the library of Aristotle. Ptolemy II Philadelphus appointed one of Eratosthenes' teachers Callimachus as the second librarian. When Ptolemy III Euergetes succeeded his father in 245 BC and he persuaded Eratosthenes to go to Alexandria as the tutor of his son Philopator. On the death of Callimachus in about 240 BC, Eratosthenes became the third librarian at Alexandria, in the library in a temple of the Muses called the Mouseion. The library is said to have contained hundreds of thousands of papyrus and vellum scrolls.

Despite being a leading all-round scholar, Eratosthenes was considered to fall short of the highest rank. Heath writes [ 4]:-

[Eratosthenes] was, indeed, recognised by his contemporaries as a man of great distinction in all branches of knowledge, though in each subject he just fell short of the highest place. On the latter ground he was called Beta, and another nickname applied to him, Pentathlos, has the same implication, representing as it does an all-round athlete who was not the first runner or wrestler but took the second prize in these contests as well as others.
Certainly this is a harsh nickname to give to a man whose accomplishments in many different areas are remembered today not only as historically important but, remarkably in many cases, still providing a basis for modern scientific methods.
One of the important works of Eratosthenes was Platonicus which dealt with the mathematics which underlie Plato's philosophy. This work was heavily used by Theon of Smyrna when he wrote Expositio rerum mathematicarum and, although Platonicus is now lost, Theon of Smyrna tells us that Eratosthenes' work studied the basic definitions of geometry and arithmetic, as well as covering such topics as music.

One rather surprising source of information concerning Eratosthenes is from a forged letter. In his commentary on Proposition 1 of Archimedes' Sphere and cylinder Book II, Eutocius reproduces a letter reputed to have been written by Eratosthenes to Ptolemy III Euergetes. The letter describes the history of the problem of the duplication of the cube and, in particular, it describes a mechanical device invented by Eratosthenes to find line segments x and y so that, for given segments a and b,

By the famous result of Hippocrates it was known that solving the problem of finding two mean proportionals between a number and its double was equivalent to solving the problem of duplicating the cube. Although the letter is a forgery, parts of it are taken from Eratosthenes' own writing. The letter, which occupies an important place in the history of mathematics, is discussed in detail in [14]. An original Arabic text of this letter was once kept in the library of the St Joseph University in Beirut. However it has now vanished and the details given in [14] come from photographs taken of the letter before its disappearance.
Other details of what Eratosthenes wrote in Platonicus are given by Theon of Smyrna. In particular he described there the history of the problem of duplicating the cube (see Heath [ 4]):-

... when the god proclaimed to the Delians through the oracle that, in order to get rid of a plague, they should construct an alter double that of the existing one, their craftsmen fell into great perplexity in their efforts to discover how a solid could be made the double of a similar solid; they therefore went to ask Plato about it, and he replied that the oracle meant, not that the god wanted an alter of double the size, but that he wished, in setting them the task, to shame the Greeks for their neglect of mathematics and their contempt of geometry.
Eratosthenes erected a column at Alexandria with an epigram inscribed on it relating to his own mechanical solution to the problem of doubling the cube [ 4]:-

If, good friend, thou mindest to obtain from any small cube a cube the double of it, and duly to change any solid figure into another, this is in thy power; thou canst find the measure of a fold, a pit, or the broad basin of a hollow well, by this method, that is, if thou thus catch between two rulers two means with their extreme ends converging. Do not thou seek to do the difficult business of Archytas's cylinders, or to cut the cone in the triads of Menaechmus, or to compass such a curved form of lines as is described by the god-fearing Eudoxus. Nay thou couldst, on these tablets, easily find a myriad of means, beginning from a small base. Happy art thou, Ptolemy, in that, as a father the equal of his son in youthful vigour, thou hast thyself given him all that is dear to muses and Kings, and may be in the future, O Zeus, god of heaven, also receive the sceptre at thy hands. Thus may it be, and let any one who sees this offering say "This is the gift of Eratosthenes of Cyrene".
Eratosthenes also worked on prime numbers . He is remembered for his prime number sieve, the 'Sieve of Eratosthenes' which, in modified form, is still an important tool in number theory research. The sieve appears in the Introduction to arithmetic by Nicomedes.
Another book written by Eratosthenes was On means and, although it is now lost, it is mentioned by Pappus as one of the great books of geometry. In the field of geodesy, however, Eratosthenes will always be remembered for his measurements of the Earth.

Eratosthenes made a surprisingly accurate measurement of the circumference of the Earth. Details were given in his treatise On the measurement of the Earth which is now lost. However, some details of these calculations appear in works by other authors such as Cleomedes, Theon of Smyrna and . Eratosthenes compared the noon shadow at midsummer between Syene (now Aswan on the Nile in Egypt) and Alexandria. He assumed that the sun was so far away that its rays were essentially parallel, and then with a knowledge of the distance between Syene and Alexandria, he gave the length of the circumference of the Earth as 250,000 .

Of course how accurate this value is depends on the length of the stadium and scholars have argued over this for a long time. The article [ 11] discusses the various values scholars have given for the stadium. It is certainly true that Eratosthenes obtained a good result, even a remarkable result if one takes 157.2 metres for the stadium as some have deduced from values given by . It is less good if 166.7 metres was the value used by Eratosthenes as Gulbekian suggests in [ 11].

Several of the papers referenced, for example [ 10], [ 15] and [ 16], discuss the accuracy of Eratosthenes' result. The paper [ 15] is particularly interesting. In it Rawlins argues convincingly that the only measurement which Eratosthenes made himself in his calculations was the zenith distance on the summer at Alexandria, and that he obtained the value of 7°12'. Rawlins argues that this is in error by 16' while other data which Eratosthenes used, from unknown sources, was considerably more accurate.

Eratosthenes also measured the distance to the sun as 804,000,000 stadia and the distance to the Moon as 780,000 stadia. He computed these distances using data obtained during lunar eclipses. Ptolemy tells us that Eratosthenes measured the tilt of the Earth's axis with great accuracy obtaining the value of ¹¹/ ₈₃ of 180°, namely 23° 51' 15".

The value ¹¹/ ₈₃ has fascinated historians of mathematics, for example the papers [ 9] and [ 17] are written just to examine the source of this value. Perhaps the most commonly held view is that the value ¹¹/ ₈₃ is due to Ptolemy and not to Eratosthenes. Heath [ 4] argues that Eratosthenes used 24° and that ¹¹/ ₈₃ of 180° was a refinement due to Ptolemy. Taisbak [ 17] agrees with attributing ¹¹/ ₈₃ to Ptolemy although he believes that Eratosthenes used the value ²/ ₁₅ of 180°. However Rawlins [ 15] believes that a continued fraction method was used to calculate the value ¹¹/ ₈₃ while Fowler [ 9] proposes that the anthyphairesis (or Euclidean algorithm ) method was used (see also [ 3]).

Eratosthenes made many other major contributions to the progress of science. He worked out a calendar that included leap years, and he laid the foundations of a systematic chronography of the world when he tried to give the dates of literary and political events from the time of the siege of Troy. He is also said to have compiled a star catalogue containing 675 stars.

Eratosthenes made major contributions to geography. He sketched, quite accurately, the route of the Nile to Khartoum, showing the two Ethiopian tributaries. He also suggested that lakes were the source of the river. A study of the Nile had been made by many scholars before Eratosthenes and they had attempted to explain the rather strange behaviour of the river, but most like Thales were quite wrong in their explanations. Eratosthenes was the first to give what is essentially the correct answer when he suggested that heavy rains sometimes fell in regions near the source of the river and that these would explain the flooding lower down the river. Another contribution that Eratosthenes made to geography was his description of the region "Eudaimon Arabia", now the Yemen, as inhabited by four different races. The situation was somewhat more complicated than that proposed by Eratosthenes, but today the names for the races proposed by Eratosthenes, namely Minaeans, Sabaeans, Qatabanians, and Hadramites, are still used.

Eratosthenes writings include the poem Hermes, inspired by astronomy, as well as literary works on the theatre and on which was a favourite topic of the Greeks. Eratosthenes is said to have became blind in old age and it has been claimed that he committed suicide by starvation.

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Eratosthenes was born in Cyrene which is now in Libya in North Africa. His teachers included the scholar Lysanias of Cyrene and the philosopher Ariston of Chios who had studied under Zeno, the founder of the school of philosophy. Eratosthenes also studied under the poet and scholar Callimachus who had also been born in Cyrene.

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In this paper we present the story of the most famous ancient female mathematician, Hypatia, and her father Theon of Alexandria.

The mathematician and philosopher Hypatia ﬂourished in Alexandria from the second part of the 4th century until her violent death incurred by a mob in 415. She was the daughter of Theon of Alexandria, a mathematician and astronomer, who ﬂourished in Alexandria during the second part of the fourth century. Information on Theon's life is only brief, coming mainly from a note in the Suda (Suida's Lexicon, written about 1000 AD) stating that he lived in Alexandria in the times of Theodosius I (who reigned AD 379-395) and taught at the Museum.

He is, in fact, the Museum's last attested member. Descriptions of two eclipses he observed in Alexandria included in his commentary to Ptolemy's Mathematical Syntaxis (Almagest) and elsewhere have been dated as the eclipses that occurred in AD 364, which is consistent with Suda.

Although originality in Theon's works cannot be claimed, he was certainly immensely inﬂuential in the preservation, dissemination and editing of classic texts of previous generations. Indeed, with the exception of Vaticanus Graecus 190 all surviving Greek manuscripts of Euclid 's Elements stem from Theon's edition. A comparison to Vaticanus Graecus 190 reveals that Theon did not actually change the mathematical content of the Elements except in minor points, but rather re-wrote it in Koini and in a form more suitable for the students he taught (some manuscripts refer to Theon's sinousiai). His edition became the classic text, far overshadowing any other version.

Creative Mathematics. Vol.12 (2003)

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In this paper we present the story of the most famous ancient female mathematician, Hypatia, and her father Theon of Alexandria. The mathematician and philosopher Hypatia ﬂourished in Alexandria from the second part of the 4th century until her violent death incurred by a mob in 415.

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17th century scientify revolution source

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I. Nicolas Copernicus (1473-1543)

A. Astronomical Background.
1. Ptolemaic astronomy, within the general framework of Aristotelian physics, dominated contemporary astronomical thought--a mathematical, nonobservational approach concerned with 'saving the phenomena'.
a. Geostatic and geocentric cosmos.
b. Celestial bodies possess uniform, circular motion around a central point.
c. Celestial bodies are composed of a fifth element, the quintessence.
d. The cosmos is finite.
3. Difficulty developed concerning the Ptolemaic use of the equant, which violated the aesthetic concept of uniform motion, and the use of epicycles, which put the center of motion on a geometric point other than a center of a deferent.
B. The Copernican System.
1. Introduced three celestial motions.
a. Diurnal rotation of the earth on its axis.
b. The earth, and the planets, revolve around the sun.
c. A conical axial motion of earth to explain the fixed orientation of earth in space.
2. Copernicus was a mathematical, not an observational, astronomer, and the mathematical apparatus of his system was as complex as Ptolemy's, employing the same geometrical devices (except the equant).
4. Copernican advantages were limited to a somewhat simpler computational technique and the introduction of a more intelligible order in the heavens, for example, removal of the ad hoc constructions needed to describe retrograde motion and the ordering of planets.

C. Motivation for the Copernican System.
1. Copernicus was educated at Cracow and Bologna in a critical atmosphere that called for the reform of Ptolemaic astronomy and cosmology.

2. Renaissance Platonic-Pythagorean influences stressed unity, coherence, and harmony in the cosmos in addition to accounting for observed phenomena.
D. The Copernican 'Revolution'
II. Johannes Kepler (1571-1630)
A. Background of Keplerian Astronomy. B. Kepler and the Tychonic System.
1. Brahe provided Kepler with the best collection of observational (empirical) data in existence.
a. Disregarded the use of equants and epicycles as a solution.
b. Formulated the Area Law: in equal time intervals a planet will sweep out equal areas (Second Law).
c. Kepler settled on the ellipse as an orbital path, that is, planetary orbits are elliptical (First Law).

C. Synopsis of Keplerian Astronomy.

III. Galileo Galilei (1564-1642)

A. Intellectual Roots of Galileo's Science. B. Galileo and Astronomy.
1. Galileo was a confirmed Copernican and given to the concept of circular motion.
a. Stellar 'population explosion' implying an expanded cosmos.
b. The topography of the moon was similar to, or more pronounced than, that of the earth; the earth-like moon moves around the earth--why can't the earth move around the sun?
c. The phases of Venus were inexplicable in terms of Ptolemaic cosmology; Ptolemaic scheme no longer viable.
d. The satellites of Jupiter, moving with, and approximately in the same plane as the planet, suggested more than one center of rotation in the solar system and, by analogy, the earth's rotation around the sun.
e. Sun spots implied that the heavens are not perfect (to reinforce the argument of the moon's topography); these data were obviously unknown to Aristotle or Ptolemy.

C. The Problem of Falling Bodies. D. Projectile Motion. E. Galileo's Method.
1. Galileo argued that theoretical conclusions required experimental verification even if the experimentation was mental rather than empirical.

IV. Rene Descartes (1596-1650) and the Mechanical Philosophy
A. Background of the Mechanical Philosophy.
1. Derived from ancient atomism but reworked by 17th century thinkers such as Descartes, Gassendi, Huygens, Hooke, and Boyle.
B. Basic Tenets of the Mechanical Philosophy. C. Cartesian Mechanical Philosophy.
1. Descartes, reacting against Renaissance skepticism, sought to affirm the existence of certain knowledge.
a. Res cogitans (thinking stuff): immaterial thought or mind.
b. Res extensa (extended stuff): geometrical extension or matter.

5. All that exists outside the mind is matter: only primary qualities exist, that is, motion, size, shape, number, location, place; secondary qualities are illusory (soft, hard, hot, cold, wet, dry, etc.).

V. Francis Bacon (1561-1626) and the Baconian Method

A. Opposition to Scholastic and Renaissance Philosophy: The Idols.
1. The Tribe: weaknesses of human nature, that is, prejudice, passions, limited mental and sensory faculties.
B. Basic Assumption: The Simplicity of Nature.
1. Scientific progress is a matter of finding the correct method, that is, the correct method is equivalent to truth:
a. If nature is approached in the appropriate manner, the truth can be found.
b. Error is the result of defective methods.

2. The ultimate goal of science is practical utility for the benefit of mankind.
C. The Baconian Method.
1. The basic premise: observe nature with the senses--proceed inductively from observations (data) to generalities (axioms), and form deductive conclusions which can be tested by experimental evidence.
a. Tabulate all possible causes of an observed effect.
b. Observe nature to see what causes actually exist in the given physical circumstances.

c. Exclude all but one, that is, the result of the crucial experiment.

VI. Isaac Newton (1642-1727) and the Newtonian Synthesis
A. Elements of the Synthetic, "New" Physics. B. The Problem and the Test Case: Lunar Motion.
1. Lunar motion was essential to both Aristotle and Newton:
a. The lunar orbit was the demarcation line for the Aristotelian two-world system (sublunar/superlunar regions).
b. The connection of lunar-terrestrial motion under the same principle was the crux of the Newtonian argument.

2. Newtonian assumptions:
a. The Copernican hypothesis: the earth is a planet.
b. The hypothesis that inter-planetary space is empty, that is, free space.

3. The problem was to explain the configuration of planetary orbits, that is, what mechanism or force can account for the orbital alteration of a planet's rectilinear path.
C. The Moon's Orbit and the Unification of Terrestrial-Celestial Physics.
1. Problem of translating the moon's rectilinear acceleration into the centripetal acceleration necessary to account for the lunar orbit--assume circular Copernican orbits.

2. Problem of demonstrating that lunar acceleration represents a ratio equivalent to that of free fall on the earth, implying the same gravitational force: the inverse square law.

D. Components of Newtonian Physics.
1. Matter: an infinite number of separate, hard, and unchangeable particles which are not identical.
2. Motion: the relational state which moves particles from place to place in an infinite void of free space without affecting them.

3. Space: the infinite homogeneous void in which the particles, and the bodies they form, move.

4. Attraction: the undefined unifying force which is not a constructive element but rather a "hyperphysical" power or mathematical statement describing how the universal components are connected.

E. The Destruction of the Aristotelian Cosmos.
1. Considerations of such concepts as perfection, harmony, teleology, formal and final causality, and value are removed from scientific discussion.
F. The Mathematical Generation of Homogeneous, Abstract Euclidean Space.
1. The common sense world of the pre-Galilean cosmos is replaced by an idealized mathematical universe.
3. The Newtonian pattern of empirical-deductive knowledge provided both physical and intellectual unity for the 18th-century universe.

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Major Figures of the Scientific Revolution - Timeline

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I. Nicolas Copernicus (1473-1543) A. Astronomical Background. 1. Ptolemaic astronomy, within the general framework of Aristotelian physics, dominated contemporary astronomical thought--a mathematical, nonobservational approach concerned with 'saving the phenomena'. a. Geostatic and geocentric cosmos. b. Celestial bodies possess uniform, circular motion around a central point.c. Celestial bodies are composed of a fifth element, the quintessence.d.

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The Copernican Planisphere, illustrated in 1661 by Andreas Cellarius.

Credit: Public domain

In the early 1500s, when virtually everyone believed Earth was the center of the universe, Polish scientist Nicolaus Copernicus proposed that the planets instead revolved around the sun. Although his model wasn't completely correct, it formed a strong foundation for future scientists to build on and improve mankind's understanding of the motion of heavenly bodies. [Related: Famous Astronomers: List of Great Scientists in Astronomy]

Indeed, other astronomers built on Copernicus' work and proved that our planet is just one world orbiting one star in a vast cosmos loaded with both, and that we're far from the center of anything. Here is a brief biography of Copernicus:

Born on Feb. 19, 1473, in Warmia, Poland, Mikolaj Kopernik (Copernicus is the Latinized form of his name) traveled to Italy at the age of 18 to attend college, where he was supposed to study the laws and regulations of the Catholic Church and return home to become a canon. However, he spent most of his time studying mathematics and astronomy. Due to his uncle's influence, Copernicus did become a canon in Warmia, but he asked to return to Italy to study medicine and to complete his law doctorate. (Of course, he may also have been thinking that the skies above Italy were clearer than above Warmia, according to Famous Scientists.

While attending the University of Bologna, he lived and worked with astronomy professor Domenico Maria de Novara, doing research and helping him make observations of the heavens. Copernicus never took orders as a priest, but instead continued to work as a secretary and physician for his uncle in Warmia.

When he returned to Poland to take up his official duties, his room in one of the towers surrounding the town boasted an observatory, giving him ample time and opportunity to study the night sky, which he did in his spare time.

In Copernicus' lifetime, most believed that Earth held its place at the center of the universe. The sun, the stars, and all of the planets revolved around it.

One of the glaring mathematical problems with this model was that the planets, on occasion, would travel backward across the sky over several nights of observation. Astronomers called this retrograde motion. To account for it, the current model, based on the Greek astronomer and mathematician Ptolemy's view, incorporated a number of circles within circles - epicycles - inside of a planet's path. Some planets required as many as seven circles, creating a cumbersome model many felt was too complicated to have naturally occurred.

In 1514, Copernicus distributed a handwritten book to his friends that set out his view of the universe. In it, he proposed that the center of the universe was not Earth, but that the sun lay near it. He also suggested that Earth's rotation accounted for the rise and setting of the sun, the movement of the stars, and that the cycle of seasons was caused by Earth's revolutions around it. Finally, he (correctly) proposed that Earth's motion through space caused the retrograde motion of the planets across the night sky (planets sometimes move in the same directions as stars, slowly across the sky from night to night, but sometimes they move in the opposite, or retrograde, direction).

Copernicus finished the first manuscript of his book, "De Revolutionibus Orbium Coelestium" ("On the Revolutions of the Heavenly Spheres") in 1532. In it, Copernicus established that the planets orbited the sun rather than the Earth. He laid out his model of the solar system and the path of the planets.

He didn't publish the book, however, until 1543, just two months before he died. He diplomatically dedicated the book to Pope Paul III. The church did not immediately condemn the book as heretical, perhaps because the printer added a note that said even though the book's theory was unusual, if it helped astronomers with their calculations, it didn't matter if it wasn't really true, according to Famous Scientists. It probably also helped that the subject was so difficult that only highly educated people could understand it. The Church did eventually ban the book in 1616.

The Catholic Church wasn't the only Christian faith to reject Copernicus' idea.

"When 'De Revolutionibus Orbium Coelestium' was published in 1543, religious leader Martin Luther voiced his opposition to the heliocentric solar system model," says Biography.com. "His underling, Lutheran minister Andreas Osiander, quickly followed suit, saying of Copernicus, 'This fool wants to turn the whole art of astronomy upside down.'"

Copernicus died on May 24, 1543, of a stroke. He was 70. He was buried in Frombork Cathedral in Poland, but in an unmarked grave. Remains thought to be his were discovered in 2005.

In 2008, researchers announced that a skull found in Frombork Cathedral did belong to the astronomer. By matching DNA from the skull to hairs found in books once owned by Copernicus, the scientists confirmed the identity of the astronomer. Polish police then used the skull to reconstruct how its owner might have looked.

Nature quotes the AFP as stating that the reconstruction "bore a striking resemblance to portraits of the young Copernicus."

In 2010, his remains were blessed with holy water by some of Poland's highest-ranking clerics before being reburied, his grave marked with a black granite tombstone decorated with a model of the solar system. The tomb marks both his scientific contribution and his service as church canon.

"Today's funeral has symbolic value in that it is a gesture of reconciliation between science and faith," Jacek Jezierski, a local bishop who encouraged the search for Copernicus, said according to the Associated Press. "Science and faith can be reconciled."

The unmarked grave was not linked to suspicions of heresy, as his ideas were only just being discussed and had yet to be forcefully condemned, according to Jack Repcheck, author of " Copernicus' Secret: How the Scientific Revolution Began."

"Why was he just buried along with everyone else, like every other canon in Frombork?" Repcheck said. "Because at the time of his death he was just any other canon in Frombork. He was not the iconic hero that he has become."

Although Copernicus' model changed the layout of the universe, it still had its faults. For one thing, Copernicus held to the classical idea that the planets traveled in perfect circles. It wasn't until the 1600s that Johannes Kepler proposed the orbits were instead ellipses. As such, Copernicus' model featured the same epicycles that marred in Ptolemy's work, although there were fewer.

Copernicus' ideas took nearly a hundred years to seriously take hold. When Galileo Galilei claimed in 1632 that Earth orbited the sun, building upon the Polish astronomer's work, he found himself under house arrest for committing heresy against the Catholic Church.

Despite this, the observations of the universe proved the two men correct in their understanding of the motion of celestial bodies. Today, we call the model of the solar system, in which the planets orbit the sun, a heliocentric or Copernican model.

"Sometimes Copernicus is honored as having substituted the old geocentric system with the new, heliocentric one, as having regarded the sun, instead of the Earth, as the unmoving center of the universe," writes Konrad Rudnick, author of the Cosmological Principles. "This view, while quite correct, does not render the actual significance of Copernicus's work."

According to Rudnick, Copernicus went beyond simply creating a model of the solar system.

"All his work involved a new cosmological principle originated by him. It is today called the Genuine Copernican Cosmological Principle and says, 'The Universe as observed from any planet looks much the same,'" Rudnick wrote.

So while Copernicus' model physically placed the sun at the center of the solar system, it also figuratively removed the focus from Earth, making it just another planet.

Follow Nola Taylor Redd at @NolaTRedd, Facebook, or Google+. Follow us at @Spacedotcom, Facebook or Google+.

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Nicolaus Copernicus Biography: Facts & Discoveries

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In the early 1500s, when virtually everyone believed Earth was the center of the universe, Polish scientist Nicolaus Copernicus proposed that the planets instead revolved around the sun. Although his model wasn't completely correct, it formed a strong foundation for future scientists to build on and improve mankind's understanding of the motion of heavenly bodies.

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1. Life and Works

Nicolaus Copernicus was born on 19 February 1473, the youngest of four children of Nicolaus Copernicus, Sr., a well-to-do merchant who had moved to Torun from Cracow, and Barbara Watzenrode, the daughter of a leading merchant family in Torun. The city, on the Vistula River, had been an important inland port in the Hanseatic League. However, fighting between the Order of the Teutonic Knights and the Prussian Union in alliance with the Kingdom of Poland ended in 1466, and West Prussia, which included Torun, was ceded to Poland, and Torun was declared a free city of the Polish kingdom. Thus the child of a German family was a subject of the Polish crown.

The father died in 1483, and the children's maternal uncle, Lucas Watzenrode (1447-1512), took them under his protection. Watzenrode was a very successful cleric - he was to become bishop of Warmia (Ermland in German) in 1489 - and he both facilitated his nephew's advancement in the church and directed his education. In 1491 Copernicus enrolled in the University of Cracow. There is no record of his having obtained a degree, which was not unusual at the time as he did not need a bachelor's degree for his ecclesiastical career or even to study for a higher degree. But the University of Cracow offered courses in mathematics, astronomy, and astrology (see Goddu 25-33 on all the university offerings), and Copernicus's interest was sparked, which is attested to by his acquisition of books in these subjects while at Cracow.

In 1495 Watzenrode arranged Copernicus's election as canon of the chapter of Frombork (Frauenberg in German) of the Cathedral Chapter of Warmia, an administrative position just below that of bishop. He assumed the post two years later, and his financial situation was secure for life. In the meantime, following in his uncle's footsteps, Copernicus went to the University of Bologna in 1496 to study canon law (see Goddu part 2 on what Copernicus may have encountered in Italy). While at Bologna he lived with the astronomy professor Domenico Maria Novara and made his first astronomical observations. In addition, as Rosen (1971, 323) noted, "In establishing close contact with Novara, Copernicus met, perhaps for the first time in his life, a mind that dared to challenge the authority of [Ptolemy] the most eminent ancient writer in his chosen fields of study." Copernicus also gave a lecture on mathematics in Rome, which may have focused on astronomy.

Copernicus's studies at Bologna provided an advantage he did not have at Cracow - a teacher of Greek. Humanism began to infiltrate the Italian universities in the fifteenth century. As Grendler (510) remarked, "By the last quarter of the century, practically all universities had one or several humanists, many of them major scholars." Antonio Cortesi Urceo, called Codro, became professor at Bologna in 1482 and added Greek several years later. Copernicus may have studied with him, for Copernicus translated into Latin the letters of the seventh-century Byzantine author Theophylactus Simocatta ( MW 27-71) from the 1499 edition of a collection of Greek letters produced by the Venetian humanist printer Aldus Manutius. Aldus had dedicated his edition to Urceo. Copernicus had his translation printed in 1509, his only publication prior to the On the Revolutions ( De revolutionibus). It is important to note that Copernicus's acquisition of a good reading knowledge of Greek was critical for his studies in astronomy because major works by Greek astronomers, including Ptolemy, had not yet been translated into Latin, the language of the universities at the time.

Copernicus left Bologna for Frombork in 1501 without having obtained his degree. The chapter then approved another leave of absence for Copernicus to study medicine at the University of Padua. The medical curriculum did not just include medicine, anatomy, and the like when Copernicus studied it. Siraisi (1990, 16) noted that "the reception in twefth-century western Europe of Greek and Islamic technical astronomy and astrology fostered the development of medical astrology...the actual practice of medical astrology was greatest in the West between the fourteenth and the sixteenth centuries." Astrology was taught in the medical schools of Italy. "The importance attached to the study of the stars in medieval medical education derived from a general and widely held belief that the heavenly bodies play an intermediary role in the creation of things here below and continue to influence them throughout their existence. The actual uses of astrology in medical diagnosis and treatment by learned physicians were many and various. 'Astrological medicine' is a vague and unsatisfactory term that can embrace any or all of the following: first, to pay attention to the supposed effect of astrological birth signs or signs at conception on the constitution and character of one's patients; second, to vary treatment according to various celestial conditions...third, to connect the doctrine of critical days in illness with astrological features, usually phases of the moon; and fourth, to predict or explain epidemics with reference to planetary conjunctions, the appearance of comets, or weather conditions" (Siraisi, 1981, 141-42). It is true that astrology required that medical students acquire some grounding in astronomy; nevertheless, it is likely that Copernicus studied astrology while at the University of Padua.

Copernicus did not receive his medical degree from Padua; the degree would have taken three years, and Copernicus had only been granted a two-year leave of absence by his chapter. Instead he matriculated in the University of Ferrara, from which he obtained a doctorate in canon law. But he did not return to his chapter in Frombork; rather he went to live with his uncle in the episcopal palace in Lidzbark-Warminski (Heilsberg in German). Although he made some astronomical observations, he was immersed in church politics, and after his elderly uncle became ill in 1507, Copernicus was his attending physician. Rosen (1971, 334-35) reasonably conjectured that the bishop may have hoped that his nephew would be his successor, but Copernicus left his uncle because his duties in Lidzbark-Warminski interfered with his continuing pursuit of his studies in astronomy. He took up residence in his chapter of Frombork in 1510 and stayed there the rest of his life.

Not that leaving his uncle and moving to Frombork exempted Copernicus from continued involvement in administrative and political duties. He was responsible for the administration of various holdings, which involved heading the provisioning fund, adjudicating disputes, attending meetings, and keeping accounts and records. In response to the problem he found with the local currency, he drafted an essay on coinage ( MW 176-215) in which he deplored the debasement of the currency and made recommendations for reform. His manuscripts were consulted by the leaders of both Prussia and Poland in their attempts to stabilize the currency. He was a leader for West Prussia in the war against the Teutonic Knights, which lasted from 1520-1525. He was physician for the bishop (his uncle had died in 1512) and members of the chapter, and he was consulting physician for notables in East and West Prussia.

Nevertheless, Copernicus began to work on astronomy on his own. Sometime between 1510 and 1514 he wrote an essay that has come to be known as the Commentariolus ( MW 75-126) that introduced his new cosmological idea, the heliocentric universe, and he sent copies to various astronomers. He continued making astronomical observations whenever he could, hampered by the poor position for observations in Frombork and his many pressing responsibilities as canon. Nevertheless, he kept working on his manuscript of On the Revolutions. He also wrote what is known as Letter against Werner ( MW 145-65) in 1524, a critique of Johann Werner's "Letter concerning the Motion of the Eighth Sphere" ( De motu octavae sphaerae tractatus primus). Copernicus claimed that Werner erred in his calculation of time and his belief that before Ptolemy the movement of the fixed stars was uniform, but Copernicus's letter did not refer to his cosmological ideas.

In 1539 a young mathematician named Georg Joachim Rheticus (1514-1574) from the University of Wittenberg came to study with Copernicus. Rheticus brought Copernicus books in mathematics, in part to show Copernicus the quality of printing that was available in the German-speaking cities. He published an introduction to Copernicus's ideas, the Narratio prima (First Report). Most importantly, he convinced Copernicus to publish On the Revolutions. Rheticus oversaw most of the printing of the book, and on 24 May 1543 Copernicus held a copy of the finished work on his deathbed.

2. Astronomical Ideas and Writings

2.1 Pre-Copernican Astronomy

Classical astronomy followed principles established by Aristotle. Aristotle accepted the idea that there were four physical elements - earth, water, air, and fire. He put the earth in the center of the universe and contended that these elements were below the moon, which was the closest celestial body. There were seven planets, or wandering stars, because they had a course through the zodiac in addition to traveling around the earth: the moon, Mercury, Venus, the sun, Mars, Jupiter. Beyond that were the fixed stars. The physical elements, according to Aristotle moved vertically, depending on their 'heaviness' or 'gravity'; the celestial bodies were not physical but a 'fifth element' or 'quintessence' whose nature was to move in perfect circles around the earth, making a daily rotation. Aristotle envisioned the earth as the true center of all the circles or 'orbs' carrying the heavenly bodies around it and all motion as 'uniform,' that is, unchanging.

But observers realized that the heavenly bodies did not move as Aristotle postulated. The earth was not the true center of the orbits and the motion was not uniform. The most obvious problem was that the outer planets seemed to stop, move backwards in 'retrograde' motion for a while, and then continue forwards. By the second century, when Ptolemy compiled his Almagest (this common name of Ptolemy's Syntaxis was derived from its Arabic title), astronomers had developed the concept that the orbit moves in 'epicycles' around a 'deferrent,' that is, they move like a flat heliacal coil around a circle around the earth. The earth was also off-center, on an 'eccentric,' as the heavenly bodies moved around a central point. Ptolemy added a point on a straight line opposite the eccentric, which is called the 'equalizing point' or the 'equant,' and around this point the heavenly bodies moved uniformly. Moreover, unlike the Aristotelian model, Ptolemy's Almagest did not describe a unified universe. The ancient astronomers who followed Ptolemy, however, were not concerned if his system did not describe the 'true' motions of the heavenly bodies; their concern was to 'save the phenomena,' that is, give a close approximation of where the heavenly bodies would be at a given point in time. And in an age without professional astronomers, let alone the telescope, Ptolemy did a good job plotting the courses of the heavenly bodies.

Not all Greek astronomical ideas followed this geocentric system. Pythagoreans suggested that the earth moved around a central fire (not the sun). Archimedes wrote that Aristarchus of Samos actually proposed that the earth rotated daily and revolved around the sun.

During the European Middle Ages, the Islamic world was the center of astronomical thought and activity. During the ninth century several aspects of Ptolemy's solar theory were recalculated. Ibn al-Haytham in the tenth-eleventh century wrote a scathing critique of Ptolemy's work: "Ptolemy assumed an arrangement that cannot exist, and the fact that this arrangement produces in his imagination the motions that belong to the planets does not free him from the error he committed in his assumed arrangement, for the existing motions of the planets cannot be the result of an arrangement that is impossible to exist" (quoted in Rosen 1984, 174). Swerdlow and Neugebauer (46-48) stressed that the thirteenth-century Maragha school was also important in finding errors and correcting Ptolemy: "The method of the Maragha planetary models was to break up the equant motion in Ptolemy's models into two or more components of uniform circular motion, physically the uniform rotation of spheres, that together control the direction and distance of the center of the epicycle, so that it comes to lie in nearly the same position it would have in Ptolemy's model, and always moves uniformly with respect to the equant." They found that Copernicus used devices that had been developed by the Maragha astronomers Nasir al-Din Tusi (1201-1274), Muayyad al-Din al-Urdi (d. 1266), Qutb al-Din al-Shirazi (1236-1311), and Ibn al-Shatir (1304-1375). In addition, Ragep, 2005, has shown that a theory for the inner planets presented by Regiomontanus that enabled Copernicus to convert the planets to eccentric models had been developed by the fifteenth-century, Samarqand-trained astronomer ali Qushji (1403-1474).

Renaissance humanism did not necessarily promote natural philosophy, but its emphasis on mastery of classical languages and texts had the side effect of promoting the sciences. Georg Peurbach (1423-1461) and (Johannes Müller) Regiomontanus (1436-1476) studied Greek for the purpose of producing an outline of Ptolemaic astronomy. By the time Regiomontanus finished the work in 1463, it was an important commentary on the Almagest as well, pointing out, for example, that Ptolemy's lunar theory did not accord with observations. He noted that Ptolemy showed the moon to be at various times twice as far from the earth as at other times, which should make the moon appear twice as big. At the time, moreover, there was active debate over Ptolemy's deviations from Aristotle's requirement of uniform circular motion.

2.2 The Commentariolus

It is impossible to date when Copernicus first began to espouse the heliocentric theory. Had he done so during his lecture in Rome, such a radical theory would have occasioned comment, but there was none, so it is likely that he adopted this theory after 1500. Further, Corvinus, who helped him print his Latin translation in 1508-09, expressed admiration for his knowledge of astronomy, so that Copernicus's concept may have still been traditional at this point. His first heliocentric writing was his Commentariolus. It was a small manuscript that was circulated but never printed. We do not know when he wrote this, but a professor in Cracow cataloged his books in 1514 and made reference to a "manuscript of six leaves expounding the theory of an author who asserts that the earth moves while the sun stands still" (Rosen, 1971, 343; MW 75). Thus, Copernicus probably adopted the heliocentric theory sometime between 1508 and 1514. Rosen (1971, 345) suggested that Copernicus's "interest in determining planetary positions in 1512-1514 may reasonably be linked with his decisions to leave his uncle's episcopal palace in 1510 and to build his own outdoor observatory in 1513." In other words, it was the result of a period of intense concentration on cosmology that was facilitated by his leaving his uncle and the attendant focus on church politics and medicine.

It is impossible to know exactly why Copernicus began to espouse the heliocentric cosmology. Despite his importance in the history of philosophy, there is a paucity of primary sources on Copernicus. His only astronomical writings were the Commentariolus, the Letter against Werner, and On the Revolutions; he published his translation of Theophylactus's letters and wrote the various versions of his treatise on coinage; other writings relate to diocesan business, as do most of the few letters that survive. Sadly, the biography by Rheticus, which should have provided scholars with an enormous amount of information, has been lost. Therefore, many of the answers to the most interesting questions about Copernicus's ideas and works have been the result of conjecture and inference, and we can only guess why Copernicus adopted the heliocentric system.

Most scholars believe that the reason Copernicus rejected Ptolemaic cosmology was because of Ptolemy's equant. They assume this because of what Copernicus wrote in the Commentariolus:

Yet the widespread [planetary theories], advanced by Ptolemy and most other [astronomers], although consistent with the numerical [data], seemed likewise to present no small difficulty. For these theories were not adequate unless they also conceived certain equalizing circles, which made the planet appear to move at all times with uniform velocity neither on its deferent sphere nor about its own [epicycle's] center...Therefore, having become aware of these [defects], I often considered whether there could perhaps be found a more reasonable arrangement of circles, from which every apparent irregularity would be derived while everything in itself would move uniformly, as is required by the rule of perfect motion. (MW 81).

Goddu (381-84) has plausibly maintained that while the initial motivation for Copernicus was dissatisfaction with the equant, that dissatisfaction may have impelled him to observe other violations of uniform circular motion, and those observations, not the rejection of the equant by itself, led to the heliocentric theory. Blumenberg (254) has pointed out that the mobility of the earth may have been reinforced by the similarity of its spherical shape to those of the heavenly bodies.

As the rejection of the equant suggests a return to the Aristotelian demand for true uniform circular motion of the heavenly bodies, it is unlikely that Copernicus adopted the heliocentric model because philosophies popular among Renaissance humanists like Neoplatonism and Hermetism compelled him in that direction. Nor should we attribute Copernicus's desire for uniform circular motions to an aesthetic need, for this idea was philosophical not aesthetic, and Copernicus's replacing the equant with epicyclets made his system more complex than Ptolemy's. Most importantly, we should bear in mind what Swerdlow and Neugebauer (59) asserted:

Copernicus arrived at the heliocentric theory by a careful analysis of planetary models - and as far as is known, he was the only person of his age to do so - and if he chose to adopt it, he did so on the basis of an equally careful analysis.

In the Commentariolus Copernicus listed assumptions that he believed solved the problems of ancient astronomy. He stated that the earth is only the center of gravity and center of the moon's orbit; that all the spheres encircle the sun, which is close to the center of the universe; that the universe is much larger than previously assumed, and the earth's distance to the sun is a small fraction of the size of the universe; that the apparent motion of the heavens and the sun is created by the motion of the earth; and that the apparent retrograde motion of the planets is created by the earth's motion. Although the Copernican model maintained epicycles moving along the deferrent, which explained retrograde motion in the Ptolemaic model, Copernicus correctly explained that the retrograde motion of the planets was only apparent not real, and its appearance was due to the fact that the observers were not at rest in the center. The work dealt very briefly with the order of the planets (Mercury, Venus, earth, Mars, Jupiter, and Saturn, the only planets that could be observed with the naked eye), the triple motion of the earth (the daily rotation, the annual revolution of its center, and the annual revolution of its inclination) that causes the sun to seem to be in motion, the motions of the equinoxes, the revolution of the moon around the earth, and the revolution of the five planets around the sun.

2.3 On the Revolutions

The Commentariolus was only intended as an introduction to Copernicus's ideas, and he wrote "the mathematical demonstrations intended for my larger work should be omitted for brevity's sake..." ( MW 82). In a sense it was an announcement of the greater work that Copernicus had begun. The Commentariolus was never published during Copernicus's lifetime, but he sent manuscript copies to various astronomers and philosophers. He received some discouragement because the heliocentric system seemed to disagree with the Bible, but mostly he was encouraged. Although Copernicus's involvement with official attempts to reform the calendar was limited to a no longer extant letter, that endeavor made a new, serious astronomical theory welcome. Fear of the reaction of ecclesiastical authorities was probably the least of the reasons why he delayed publishing his book. The most important reasons for the delay was that the larger work required both astronomical observations and intricate mathematical proofs. His administrative duties certainly interfered with both the research and the writing. He was unable to make the regular observations that he needed and Frombork, which was often fogged in, was not a good place for those observations. Moreover, as Gingerich (1993, 37) pointed out,

[Copernicus] was far from the major international centers of printing that could profitably handle a book as large and technical as De revolutionibus. On the other [hand], his manuscript was still full of numerical inconsistencies, and he knew very well that he had not taken complete advantage of the opportunities that the heliocentric viewpoint offered...Furthermore, Copernicus was far from academic centers, thereby lacking the stimulation of technically trained colleagues with whom he could discuss his work.

The manuscript of On the Revolutions was basically complete when Rheticus came to visit him in 1539. The work comprised six books. The first book, the best known, discussed what came to be known as the Copernican theory and what is Copernicus's most important contribution to astronomy, the heliocentric universe (although in Copernicus's model, the sun is not truly in the center). Book 1 set out the order of the heavenly bodies about the sun: "[The sphere of the fixed stars] is followed by the first of the planets, Saturn, which completes its circuit in 30 years. After Saturn, Jupiter accomplishes its revolution in 12 years. The Mars revolves in 2 years. The annual revolution takes the series' fourth place, which contains the earth...together with the lunar sphere as an epicycle. In the fifth place Venus returns in 9 months. Lastly, the sixth place is held by Mercury, which revolves in a period of 80 days" ( Revolutions, 21-22). This established a relationship between the order of the planets and their periods, and it made a unified system. This may be the most important argument in favor of the heliocentric model as Copernicus described it. It was far superior to Ptolemy's model, which had the planets revolving around the earth so that the sun, Mercury, and Venus all had the same annual revolution. In book 1 Copernicus also insisted that the movements of all bodies must be circular and uniform, and noted that the reason they may appear nonuniform to us is "either that their circles have poles different [from the earth's] or that the earth is not at the center of the circles on which they revolve" ( Revolutions, 11). Particularly notable for Copernicus was that in Ptolemy's model the sun, the moon, and the five planets seemed ironically to have different motions from the other heavenly bodies and it made more sense for the small earth to move than the immense heavens. But the fact that Copernicus turned the earth into a planet did not cause him to reject Aristotelian physics, for he maintained that "land and water together press upon a single center of gravity; that the earth has no other center of magnitude; that, since earth is heavier, its gaps are filled with water..." ( Revolutions, 10). As Aristotle had asserted, the earth was the center toward which the physical elements gravitate. This was a problem for Copernicus's model, because if the earth was no longer the center, why should elements gravitate toward it?

The second book of On the Revolutions elaborated the concepts in the first book; book 3 dealt with the precession of the equinoxes and solar theory; book 4 dealt with the moon's motions; book 5 dealt with the planetary longitude and book 6 with latitude. Copernicus depended very much on Ptolemy's observations, and there was little new in his mathematics. He was most successful in his work on planetary longitude, which, as Swerdlow and Neugebauer (77) commented, was "Copernicus's most admirable, and most demanding, accomplishment...It was above all the decision to derive new elements for the planets that delayed for nearly half a lifetime Copernicus's continuation of his work - nearly twenty years devoted to observation and then several more to the most tedious kind of computation - and the result was recognized by his contemporaries as the equal of Ptolemy's accomplishment, which was surely the highest praise for an astronomer." Surprisingly, given that the elimination of the equant was so important in the Commentariolus, Copernicus did not mention it in book 1, but he sought to replace it with an epicyclet throughout On the Revolutions. Nevertheless, he did write in book 5 when describing the motion of Mercury:

...the ancients allowed the epicycle to move uniformly only around the equant's center. This procedure was in gross conflict with the true center [of the epicycle's motion], its relative [distances], and the prior centers of both [other circles]...However, in order that this last planet too may be rescued from the affronts and pretenses of its detractors, and that its uniform motion, no less than that of the other aforementioned planets, may be revealed in relation to the earth's motion, I shall attribute to it too, [as the circle mounted] on its eccentric, an eccentric instead of the epicycle accepted in antiquity (Revolutions, 278-79).

2.4 Rheticus and the Narratio prima

Although Copernicus received encouragement to publish his book from his close friend, the bishop of Chelmo Tiedemann Giese (1480-1550), and from the cardinal of Capua Nicholas Schönberg (1472-1537), it was the arrival of Georg Joachim Rheticus in Frombork that solved his needs for a supportive and stimulating colleague in mathematics and astronomy and for access to an appropriate printer. Rheticus was a professor of mathematics at the University of Wittenberg, a major center for the student of mathematics as well as for Lutheran theology. In 1538 Rheticus took a leave of absence to visit several famous scholars in the fields of astronomy and mathematics. It is not known how Rheticus learned about Copernicus's theory; he may have been convinced to visit Copernicus by one of the earlier scholars he had visited, Johann Schöner, though, as Swerdlow and Neugebauer (16) noted, by "the early 1530's knowledge of Copernicus's new theory was circulating in Europe, even reaching the high and learned circles of the Vatican." Rheticus brought with him some mathematical and astronomical volumes, which both provided Copernicus with some important material and showed him the quality of the mathematical printing available in the German centers of publishing. Rheticus's present of the 1533 edition of Regiomontanus's On all Kinds of Triangles ( De triangulis omnimodis), for example, convinced Copernicus to revise his section on trigonometry. But Rheticus was particularly interested in showing Copernicus the work of the Nuremberg publisher Johann Petreius as a possible publisher of Copernicus's volume. Swerdlow and Neugebauer (25) plausibly suggested that "Petreius was offering to publish Copernicus's work, if not advertising by this notice that he was already committed to do so." Rheticus wrote the Narratio prima in 1540, an introduction to the theories of Copernicus, which was published and circulated. This further encouraged Copernicus to publish his Revolutions, which he had been working on since he published the Commentariolus.

The Narratio prima was written in 1539 and took the form of a letter to Johann Schöner announcing Copernicus's findings and describing the contents of the Revolutions. He dealt with such topics as the motions of the fixed stars, the tropical year, the obliquity of the ecliptic, the problems resulting from the motion of the sun, the motions of the earth and the other planets, librations, longitude in the other five planets, and the apparent deviation of the planets from the ecliptic. He asserted that the heliocentric universe should have been adopted because it better accounted for such phenomena as the precession of the equinoxes and the change in the obliquity of the ecliptic; it resulted in a diminution of the eccentricity of the sun; the sun was the center of the deferents of the planets; it allowed the circles in the universe to revolve uniformly and regularly; it satisfied appearances more readily with fewer explanations necessary; it united all the spheres into one system. Rheticus added astrological predictions and number mysticism, which were absent from Copernicus's work.

The Narratio prima was printed in 1540 in Gdansk (then Danzig); thus, it was the first printed description of the Copernican thesis. Rheticus sent a copy to Achilles Pirmin Gasser of Feldkirch, his hometown in modern-day Austria, and Gasser wrote a foreword that was published with a second edition that was produced in 1541 in Basel. It was published again in 1596 as an appendix to the first edition of Johannes Kepler's Mysterium cosmographicum (Secret of the Universe), the first completely Copernican work by an adherent since the publications by Copernicus and Rheticus.

2.5 Printing On the Revolutions and Osiander's Preface

The publication of Rheticus's Narratio prima did not create a big stir against the heliocentric thesis, and so Copernicus decided to publish On the Revolutions. He added a dedication to Pope Paul III (r. 1534-1549), probably for political reasons, in which he expressed his hesitancy about publishing the work and the reasons he finally decided to publish it. He gave credit to Schönberg and Giese for encouraging him to publish and omitted mention of Rheticus, but it would have been insulting to the pope during the tense period of the Reformation to give credit to a Protestant minister. He dismissed critics who might have claimed that it was against the Bible by giving the example of the fourth-century Christian apologist Lactantius, who had rejected the spherical shape of the earth, and by asserting, "Astronomy is written for astronomers" ( Revolutions, 5). In other words, theologians should not meddle with it. He pointed to the difficulty of calendar reform because the motions of the heavenly bodies were inadequately known. And he called attention to the fact that "if the motions of the other planets are correlated with the orbiting of the earth, and are computed for the revolution of each planet, not only do their phenomena follow therefrom but also the order and size of all the planets and spheres, and heaven itself is so linked together that in no portion of it can anything be shifted without disrupting the remaining parts and the universe as a whole" ( Revolutions, 5).

Rheticus returned to Wittenberg in 1541 and the following year received another leave of absence, at which time he took the manuscript of the Revolutions to Petreius for publishing in Nuremberg. Rheticus oversaw the printing of most of the text. However, Rheticus was forced to leave Nuremberg later that year because he was appointed professor of mathematics at the University of Leipzig. He left the rest of the management of printing the Revolutions to Andrew Osiander (1498-1552), a Lutheran minister who was also interested in mathematics and astronomy. Though he saw the project through, Osiander appended an anonymous preface to the work. In it he claimed that Copernicus was offering a hypothesis, not a true account of the working of the heavens: "Since he [the astronomer] cannot in any way attain to the true causes, he will adopt whatever suppositions enable the motions to be computed correctly from the principles of geometry for the future as well as for the past ...these hypotheses need not be true nor even probable" ( Revolutions, xvi). This clearly contradicted the body of the work. Both Rheticus and Giese protested, and Rheticus crossed it out in his copy.

2.6 Sixteenth Century Reactions to On the Revolutions

Copernicus's fame and book made its way across Europe over the next fifty years, and a second edition was brought out in 1566. As Gingerich's census of the extant copies showed, the book was read and commented on by astronomers. (For a fuller discussion of reactions, see Omodeo.) Gingerich (2004, 55) noted "the majority of sixteenth-century astronomers thought eliminating the equant was Copernicus' big achievement."

While Martin Luther may have made negative comments about Copernicus because the idea of the heliocentric universe seemed to contradict the Bible, Philip Melanchthon (1497-1560), who presided over the curriculum at the University of Wittenberg, eventually accepted the importance of teaching Copernicus's ideas, perhaps because Osiander's preface made the work more palatable. His son-in-law Caspar Peucer (1525-1602) taught astronomy there and began teaching Copernicus's work. As a result, the University of Wittenberg became a center where Copernicus's work was studied. But Rheticus was the only Wittenberg scholar who accepted the heliocentric idea. Robert Westman (1975a, 166-67; 2011, chap. 5) suggested that there was a 'Wittenberg Interpretation': astronomers appreciated and adopted some of Copernicus's mathematical models but rejected his cosmology, and some were pleased with his replacement of the equant by epicyclets. One of these was Erasmus Reinhold (1511-1553), a leading astronomer at Wittenberg who became dean and rector. He produced a new set of planetary tables from Copernicus's work, the Prutenic Tables. Although, as Gingerich (1993, 232) pointed out, "there was relatively little to distinguish between the accuracy of the Alfonsine Tables and the Prutenic Tables," the latter were more widely adopted; Gingerich plausibly suggested that the fact that the Prutenic Tables more accurately predicted a conjunction between Jupiter and Saturn in 1563 made the difference. Reinhold did not accept the heliocentric theory, but he admired the elimination of the equant. The Prutenic Tables excited interest in Copernicus's work.

Tycho Brahe (1546-1601) was the greatest astronomical observer before the invention of the telescope. He called Copernicus a 'second Ptolemy' (quoted in Westman 1975, 307) and appreciated both the elimination of the equant and the creation of a planetary system. But Tycho could not adopt the Copernican system, partly for the religious reason that it went against what the Bible seemed to preach. He, therefore, adopted a compromise, the 'geoheliostatic' system in which the two inner planets revolved around the sun and that system along with the rest of the planets revolved around the earth.

Among Catholics, Christoph Clavius (1537-1612) was the leading astronomer in the sixteenth century. A Jesuit himself, he incorporated astronomy into the Jesuit curriculum and was the principal scholar behind the creation of the Gregorian calendar. Like the Wittenberg astronomers, Clavius adopted Copernican mathematical models when he felt them superior, but he believed that Ptolemy's cosmology - both his ordering of the planets and his use of the equant - was correct.

Pope Clement VII (r. 1523-1534) had reacted favorably to a talk about Copernicus's theories, rewarding the speaker with a rare manuscript. There is no indication of how Pope Paul III, to whom On the Revolutions was dedicated reacted; however, a trusted advisor, Bartolomeo Spina of Pisa (1474-1546) intended to condemn it but fell ill and died before his plan was carried out (see Rosen, 1975). Thus, in 1600 there was no official Catholic position on the Copernican system, and it was certainly not a heresy. When Giordano Bruno (1548-1600) was burned at the stake as a heretic, it had nothing to do with his writings in support of Copernican cosmology, and this is clearly shown in Finocchiaro's reconstruction of the accusations against Bruno (see also Blumenberg's part 3, chapter 5, titled "Not a Martyr for Copernicanism: Giordano Bruno").

Michael Maestlin (1550-1631) of the University of Tübingen was the earliest astronomer after Rheticus to adopt Copernicus's heliocentricism. Although he wrote a popular textbook that was geocentric, he taught his students that the heliocentric system was superior. He also rejected Osiander's preface. Maestlin's pupil Johannes Kepler wrote the first book since the publication of On the Revolutions that was openly heliocentric in its orientation, the Mysterium cosmographicum (Secret of the Universe). And, of course, Kepler eventually built on Copernicus's work to create a much more accurate description of the solar system.

Bibliography

A. Complete Works of Copernicus

In 1972 the Polish Academy of Sciences under the direction of J. Dobrzycki published critical editions of the Complete Works of Copernicus in six languages: Latin, English, French, German, Polish, and Russian. The first volume was a facsimile edition. The annotations in the English translations are more comprehensive than the others. The English edition was reissued as follows:

Minor Works, 1992, trans. E. Rosen, Baltimore: The Johns Hopkins University Press (originally published as volume 3 ofNicholas Copernicus: Complete Works, Warsaw: Polish Scientific Publishers, 1985). Referred to herein asMW.

On the Revolutions, 1992, trans. E. Rosen, Baltimore: The Johns Hopkins University Press (originally published as volume 2 ofNicholas Copernicus: Complete Works, Warsaw: Polish Scientific Publishers, 1978). Referred to herein asRevolutions.

B. Other Translations of Copernicus's Works

On the Revolutions of the Heavenly Spheres, 1955, trans. C.G. Wallis, vol. 16 ofGreat Books of the Western World, Chicago: Encyclopedia Britannica; 1995, reprint, Amherst: Prometheus Books.

On the Revolutions of the Heavenly Spheres, 1976, trans. and ed. A.M. Duncan, Newton Abbot: David & Charles.

"The Derivation and First Draft of Copernicus's Planetary Theory: A Translation of the Commentariolus with Commentary," 1973, trans. N.M. Swerdlow, Proceedings of the American Philosophical Society, 117: 423-512.

C. Translations of Other Primary Sources

Bruno, G., 1977, The Ash Wednesday Supper, trans. E.A. Gosselin and L.S. Lerner, Hamden: Archon Books, 1995; reprint, Toronto: University of Toronto Press.

Rheticus, G.J., Narratio prima, in E. Rosen, 1971, 107-96.

D. Secondary Sources

Blåsjö, V., 2014, "A Critique of the Arguments for Maragha Influence on Copernicus," Journal for the History of Astronomy, 45: 183-195.

Blumenberg, H., 1987, The Genesis of the Copernican World, trans. R.M. Wallace, Cambridge, MA: MIT Press.

Cohen, I.B., 1960, The Birth of a New Physics, Garden City: Anchor Books; rev. ed., New York: W.W. Norton, 1985.

---, 1985, Revolutions in Science, Cambridge, MA: Harvard University Press.

Crowe, M.J., 1990, Theories of the World from Antiquity to the Copernican Revolution, New York: Dover Publications.

Feldhay, R. and F.J. Ragep (eds.), 2017, Before Copernicus: The Cultures and Contexts of Scientific Learning in the Fifteenth Century, Montreal: McGill-Queens University Press.

Finocchiaro, M.A., 2002, "Philosophy versus Religion and Science versus Religion: the Trials of Bruno and Galileo," in H. Gatti (ed.), 51-96.

Gatti, H. (ed.), 2002, Giordano Bruno: Philosopher of the Renaissance, Aldershot: Ashgate.

Gillespie, C.C. (ed.), 1970-80, Dictionary of Scientific Biography, New York: Scribner's.

Gingerich, O., 1993, The Eye of Heaven: Ptolemy, Copernicus, Kepler, New York: American Institute of Physics.

---, 2002, An Annotated Census of Copernicus' De revolutionibus, Leiden: Brill Academic Publishers; Nuremberg, 1543 and Basel, 1566.

---, 2004, The Book Nobody Read: Chasing the Revolutions of Nicolaus Copernicus, New York: Walker & Company.

Goldstein, B., 2002, "Copernicus and the Origin of His Heliocentric System," Journal for the History of Astronomy, 33: 219-235.

Goddu, A., 2010, Copernicus and the Aristotelian Tradition: Education, Reading, and Philosophy in Copernicus's Path to Heliocentrism, Leiden: Brill.

Grendler, P., 2002, The Universities of the Italian Renaissance, Baltimore: The Johns Hopkins University Press.

Hallyn, F., 1990, The Poetic Structure of the World: Copernicus and Kepler, trans. D. Leslie, New York: Zone Books.

Koestler, A., 1989, The Sleepwalkers, London: Penguin, reprint of 1959 edition.

Koyré, A., 1957, From the Closed World to the Infinite Universe, Baltimore: The Johns Hopkins University Press.

---, 1973, The Astronomical Revolution: Copernicus, Kepler, Borelli, trans. R.E.W. Maddison, Ithaca: Cornell University Press.

Kuhn, T., 1957, The Copernican Revolution, Cambridge, MA: Harvard University Press.

Morrison, R., 2014, "A Scholarly Intermediary between the Ottoman Empire and Renaissance Europe," Isis, 105: 32-57.

---, 2017, "Jews as Scientific Intermediaries in the European Renaissance," in Feldhay and Ragep (eds.), 198-214-97.

Omodeo, P.D., 2014, Copernicus in the Cultural Debates of the Renaissance: Reception, Legacy, Transformation, Leiden: Brill.

Ragep, F.J., 2005, "Ali Qushji and Regiomontanus," Journal for the History of Astronomy, 36: 359-71.

---, 2007, "Copernicus and His Islamic Predecessors," History of Science, 45: 65-81.

---, 2016, "Ibn al-Shatir and Copernicus: The Uppsala Notes Revisited," Journal for the History of Astronomy, 47: 395-415.

---, 2017, "From Tun to Turin: The Twists and Turns of the Tusi Couple," in Feldhay and Ragep (eds.), 161-97.

Rosen, E.,1970a, "Copernicus," in Gillespie (ed.), 3: 401-11.

---, 1970b, "Rheticus," Gillespie (ed.), 11: 395-97.

---, 1971, Three Copernican Treatises, 3d ed., New York: Octagon Books.

---, 1975, "Was Copernicus' Revolutions Approved by the Pope?"Journal of the History of Ideas, 36: 531-42.

---, 1984, Copernicus and the Scientific Revolution, Malabar, FL: Krieger Publishing Co.

Saliba, G., 2007, Islamic Science and the Making of the European Renaissance, Cambridge, MA: MIT Press.

Shumaker, W., 1979, The Occult Sciences in the Renaissance: A Study in Intellectual Patterns, Berkeley: University of California Press, reprint of 1972 edition.

Siraisi, N., 1981, Taddeo Alderotti and His Pupils: Two Generations of Italian Medical Learning, Princeton: Princeton University Press.

---, 1990, Medieval and Early Renaissance Medicine: An Introduction to Knowledge and Practice, Chicago: University of Chicago Press.

Swerdlow, N., 2000, "Copernicus, Nicolaus (1473-1543)," in Encyclopedia of the Scientific Revolution, W. Applebaum (ed.), New York: Garland Publishing, 162-68.

---, 2017, "Copernicus's Derivation of the Heliocentric Theory from Regiomontanus's Eccentric Models of the Second Inequality of the Superior and Inferior Planets" Journal for the History of Astronomy, 48: 33-61.

Swerdlow, N. and O. Neugebauer, 1984, Mathematical Astronomy in Copernicus's De Revolutionibus, 2 vols., New York: Springer-Verlag.

Westman, R., 1975a, "The Melanchthon Circle, Rheticus, and the Wittenberg Interpretation of the Copernican Theory," Isis, 66: 165-93.

---, 1975b, "Three Responses to the Copernican Theory: Johannes Praetorius, Tycho Brahe, and Michael Maestlin," in Westman (ed.), 1975c.

---, (ed), 1975c, The Copernican Achievement, Berkeley: University of California Press.

---, 2011, The Copernican Question: Prognostication, Skepticism, and Celestial Order, Berkeley: University of California Press.

Yates, F., 1979, Giordano Bruno and the Hermetic Tradition, Chicago: University of Chicago Press, reprint of 1964 edition.

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Nicolaus Copernicus was born on 19 February 1473, the youngest of four children of Nicolaus Copernicus, Sr., a well-to-do merchant who had moved to Torun from Cracow, and Barbara Watzenrode, the daughter of a leading merchant family in Torun. The city, on the Vistula River, had been an important inland port in the Hanseatic League.

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Starts talking about Alexandria arounf

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The Library of Alexandria, one of the wonders of the Ancient World, has haunted Western culture for over 2,000 years. The Ptolemaic kings of Egypt-successors of Alexander the Great-had a staggering ambition: to house all of the books ever written under one roof, and the story of the universal library and its destruction still has the power to move us.But what was the library, and where was it?

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Once the largest library in the ancient world, and containing works by the greatest thinkers and writers of antiquity, including Homer, Plato, Socrates and many more, the Library of Alexandria, northern Egypt, is popularly believed to have been destroyed in a huge fire around 2000 years ago and its volumous works lost.

Since its destruction this wonder of the ancient world has haunted the imagination of poets, historians, travellers and scholars, who have lamented the tragic loss of knowledge and literature. Today, the idea of a 'Universal Library' situated in a city celebrated as the centre of learning in the ancient world, has attained mythical status.

The mystery has been perpetuated by the fact that no architectural remains or archaeological finds that can definitely be attributed to the ancient Library have ever been recovered, surprising for such a supposedly renowned and imposing structure. This lack of physical proof has even persuaded some to wonder if the fabulous Library actually existed at all in the form popularly imagined.

Ancient Alexandria

Once home to the massive Pharos lighthouse, one of the Seven Wonder of the Ancient World, the Mediterranean seaport of Alexandria was founded by Alexander the Great around 330 BCE, and like many other cities in his Empire, took its name from him. After his death in 323 BCE, Alexander's Empire was left in the hands of his generals, with Ptolemy I Soter taking Egypt and making Alexandria his capital in 320 BCE. Formerly a small fishing village on the Nile delta, Alexandria became the seat of the Ptolemaic rulers of Egypt and developed into a great intellectual and cultural centre, perhaps the greatest city in the ancient world.

The Origins of the Ancient Library

Demetrius organised the construction of the ' Temple of the Muses' or 'the Musaeum', from where our word 'museum' is derived.

The founding of the Library of Alexandria, actually two or more libraries, is obscure. It is believed that around 295 BCE, the scholar and orator Demetrius of Phalerum, an exiled governor of Athens, convinced Ptolemy I Soter to establish the Library. Demetrius envisioned a library that would house a copy of every book in the world, an institution to rival those of Athens itself. Subsequently, under the patronage of Ptolemy I, Demetrius organised the construction of the 'Temple of the Muses' or 'the Musaeum', from where our word 'museum' is derived. This structure was a shrine complex modeled on the Lyceum of Aristotle in Athens, a centre for intellectual and philosophical lectures and discussion.

The Temple of the Muses was to be the first part of the library complex at Alexandria, and was located within the grounds of the Royal Palace, in an area known as the Bruchion or palace quarter, in the Greek district of the city. The Museum was a cult centre with shrines for each of the nine muses, but also functioned as a place of study with lecture areas, laboratories, observatories, botanical gardens, a zoo, living quarters, and dining halls, as well as the Library itself. A priest chosen by Ptolemy I himself was the administrator of the Museum, and there was also a separate Librarian in charge of the manuscript collection. At some time during his reign from 282 BCE to 246 BCE, Ptolemy II Philadelphus, the son of Ptolemy I Soter, established the 'Royal Library' to complement the Temple of the Muses set up by his father.

It is not clear whether the Royal Library, which was to become the main manuscript Library, was a separate building located next to the Museum or was an extension of it. However, the consensus of opinion is that the Royal Library did form part of the Temple of the Muses.

During the reign of Ptolemy II, the idea of the Universal Library seems to have taken shape. Apparently more than 100 scholars were housed within the Museum, whose job it was to carry out scientific research, lecture, publish, translate, copy and collect not only original manuscripts of Greek authors (allegedly including the private collection of Aristotle himself), but translations of works from Egypt, Assyria, Persia, as well as Buddhist texts and Hebrew scriptures.

One story goes that the hunger of Ptolemy III for knowledge was so great that he decreed that all ships docking at the port should surrender their manuscripts to the authorities. Copies were then made by official scribes and delivered to the original owners, the originals being filed away in the Library.

An often quoted figure for the ancient Library holdings at its peak is half a million documents, though whether this refers to the amount of books or the number of papyrus scrolls is unclear. However, in view of the fact that many papyrus rolls were needed to make up an entire book, it is more likely that it refers to the number of scrolls. Even 500,000 scrolls has been thought too high by some scholars, as the construction of a building with such a vast amount of storage space would be an immense, though not impossible undertaking. Nevertheless, during the reign of Ptolemy II the collection at the Royal Library became so vast that a daughter library was established. This library was situated in the precincts of the temple of Serapis, in the Egyptian district of Rhakotis, in the south eastern part of the city. During the librarianship of the Greek writer Callimachus (c. 305 BCE - c . 240 BCE), the daughter library contained 42,800 scrolls, all of which were copies of those in the main Library.

The Burning of the Great Library?

The infamous destruction by fire of the Library of Alexandria, with the consequent loss of the most complete collection of ancient literature ever assembled, has been a point of heated debate for centuries. What exactly happened to this amazing storehouse of ancient knowledge, and who was responsible for its burning? However, it is probable 'the greatest catastrophe of the ancient world', may never have taken place on the scale often supposed.

The prime suspect in destruction of the Library of Alexandria is Julius Caesar. It is alleged that during Caesar's occupation of the city of Alexandria in 48 BCE, he found himself in the Royal Palace, hemmed in by the Egyptian fleet in the harbour. For his own safety he had his men set fire to the Egyptian ships, but the fire got out of control and spread to the parts of the city nearest the shore, which included warehouses, depots and some arsenals.

After Julius Caesar's death it was generally believed that it was he who had destroyed the Library.

After Caesar's death it was generally believed that it was he who had destroyed the Library. Roman philosopher and dramatist Seneca, quoting from Livy's History of Rome, written between 63 BCE and 14 CE, says that 40,000 scrolls were destroyed in the fire started by Caesar. Greek historian Plutarch (died 120 CE) mentions that the fire destroyed 'the great Library' and Roman historian Dio Cassius (c. 165 - 235 CE) mentions a warehouse of manuscripts being destroyed during the conflagration.

In his book The Vanished Library, Luciano Canfora interprets the evidence from ancient writers to indicate the destruction of manuscripts stored in warehouses near the port waiting for export, rather than the great Library itself. The great scholar and stoic philosopher Strabo, was working in Alexandria in 20 BC and from his writings it is obvious that the Library was not at that time the world-renowned centre for learning it had been in previous centuries. In fact Strabo does not mention a library as such at all, though he does mention the Museum, which he describes as 'part of the royal palace'. He goes on to say that 'it comprises the covered walk, the exedra or portico, and a great hall in which the learned members of the Museum take their meals in common.'

If the great Library was attached to the Museum then Strabo obviously felt there was no need to mention it separately, and, perhaps more importantly, if he was there in 20 BCE, the Library had obviously not been burned down by Caesar twenty-eight years previously. The existence of the Library in 20 BCE, though in a much less complete form, means that we have to look to someone other than Caesar as the destroyer of Alexandria's ancient wonder.

In 391 CE, as part of his attempt to wipe out paganism, Emperor Theodosius I officially sanctioned the destruction of the Serapeum, or Temple of Serapis at Alexandria. The destruction of the Temple was carried out under Theophilus, Bishop of Alexandria, and afterwards a Christian church was built on the site. It has been hypothesised that the daughter library of the Museum, located close to the Temple, and the Royal Library were also razed to the ground at this time. However, whilst it is plausible that manuscripts from the Serapeum library may have been destroyed during this purge, there is no evidence that the Royal Library still existed at the end the 4th century. No ancient sources mention the destruction of any library at this time, though 18th century English historian Edward Gibbon mistakenly attributes it to bishop Theophilus.

The last suggested perpetrator of the crime is the Caliph Omar. In 640 CE the Arabs under General Amrou ibn el-Ass, captured Alexandria after a long siege. According to the story, the conquering Arabs heard about a magnificent library containing all the knowledge of the world and were anxious to see it. But the Caliph, unmoved by this vast collection of learning, apparently stated 'they will either contradict the Koran, in which case they are heresy, or they will agree with it, so they are superfluous.'

The manuscripts were then gathered together and used as fuel for the 4,000 bathhouses in the city. In fact there were so many scrolls that they kept the bathhouses of Alexandria heated for six months. These incredible facts were written down 300 years after the supposed event by Christian polymath Gregory Bar Hebraeus (1226-1286 CE). However, while the Arabs may have destroyed a Christian library at Alexandria, it is almost certain that by the mid 7th century CE the Royal Library no longer existed. This is made clear by the fact that no mention is made of such a catastrophic event by contemporary writers such as Christian chronicler John of Nikiou, Byzantine monk and writer John Moschus and Sophronius, Patriarch of Jerusalem.

The Volatile City of Alexandria

Attempting to identify one single devastating fire that destroyed the great Library and all of its holdings is a futile task. Alexandria was often a volatile city, especially during the Roman period, as witnessed by Caesar's burning of the ships, and also in the violent struggle between the occupying forces of Queen Zenobia of Palmyra and the Roman emperor Aurelian in 270-71 CE. Aurelian eventually recovered the city for Rome from Queen Zenobia's armies, but not before many parts of Alexandria had been devastated, and the Bruchion district, which contained the palace and the Library, were apparently 'made into a desert'.

The city was again sacked a few years later by Roman Emperor Diocletian. Such repeated destruction spread over several centuries, along with neglect of the Library's contents as people's opinions and affiliations changed, means that the 'catastrophe' that ended the ancient Library at Alexandria was gradual, taking place over a period of four or five hundred years.

The last recorded Director of the great Library was scholar and mathematician Theon (c. 335 - c. 405 CE), father of the female philosopher Hypatia, brutally murdered by a Christian mob in Alexandria in 415 CE. Perhaps one day, in the deserts of Egypt, scrolls that were once part of the great Library will be discovered. Many archaeologists believe that the buildings that once composed the legendary seat of learning at ancient Alexandria, if not buried under the modern metropolis, could still survive relatively intact somewhere in the north-eastern part of the city.

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What happened to the Great Library at Alexandria?

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Once the largest library in the ancient world, and containing works by the greatest thinkers and writers of antiquity, including Homer, Plato, Socrates and many more, the Library of Alexandria, northern Egypt, is popularly believed to have been destroyed in a huge fire around 2000 years ago and its volumous works lost.

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Amazing History Of Library Of Alexandria

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The Amazing History Of Library Of Alexandria - Full Documentary

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The Amazing History Of Library Of Alexandria - Full Documentary The Royal Library of Alexandria or Ancient Library of Alexandria in Alexandria, Egypt, was one of the largest and most significant libraries of the ancient world. It was dedicated to the Muses, the nine goddesses of the arts.

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Stuff about Caesar at Alexandria around 48.

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An English translation. All of Plutarch's Lives are onsite; in turn part of a very large site on classical Antiquity.

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Roman historian talking about the library. chapter 16 starts talking about Alexandria at 7

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LacusCurtius * Ammianus Marcellinus - Book XXII

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Part of a complete English translation. Site contains many Greek and Latin texts, translations and related material.

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Aristarchus of Samos!!!!
Earth revolves around sun order of planets universe doesn't revolve around earth all work destroyed set back centuries.

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Aristarchus of Samos (c. 310 - c. 230 BCE) was an ancient Greek mathematician and astronomer from Ionia who came up with a revolutionary astronomical hypothesis. He claimed the Sun, not the Earth, was the fixed centre of the universe, and that the Earth, along with the rest of the planets, revolved around the Sun. He also said that the stars were distant suns that remained unmoved and that the size of the universe was much larger than his contemporaries believed.

This Sun-centred view of the universe is often referred to as "heliocentric". It is fair to say that while the term heliocentric seems to be relatively adequate to classify Aristarchus view, it nevertheless fails to address the fact that Aristarchus' hypothesis had a number of additional interesting implications far beyond just a Sun-centred planetary system and a rotating Earth. In fact, a rotating Earth was already held by Heraclides Ponticus (390 BCE - 310 BCE) some time before Aristarchus and the Pythagorean tradition believed that the Earth was not the centre of the universe, but that it revolved around the "Central fire", an imaginary body believed by them to be the actual source of the light of the universe.

Historical Context

Just like Egypt influence caused Greek mathematics to flourish a number of centuries before, the influence of Babylon had an equivalent stimulus over Greek astronomy. Alexander the Great's opening of the East led to an exchange of ideas that had a critical input into Greek's astronomical notions. This is the context in which Aristarchus developed his theory.

The general consensus among Greek astronomers during the time Aristarchus lived was that the universe was Earth-centred.

Except for a few rare exceptions, the general consensus among Greek astronomers during the time Aristarchus lived was that the universe was Earth-centred. During the 4th century BCE, Plato and Aristotle defended the geocentric model but both philosophers did so using mostly mystical and mythical arguments. The stars and planets were carried around the Earth on spheres, arranged in a concentric fashion. Plato even described the universe as the Spindle of Necessity, attended by the Sirens and turned by the three Fates. There was little room in Plato's views for the idea of a universe governed by natural laws, since he rejected any form of determinism. In fact, the unpredictable motions of some planets (especially Mars), were seen by Plato as proof that natural laws could not account for all the changes in the universe. Eudoxus, a student of Plato, challenged the views of his teacher by working on a more myth-free mathematical model, but the idea of concentric spheres and circular planetary motion still persisted.

Despite the general consensus on the Earth-centred model, there were a number of reasons that led some to believe that the model was not fully accurate and needed some corrections. For example, it was not possible for the geocentric model to explain either the changes in the brightness of the planets or their retrograde motions. Aristarchus' hypothesis was developed as an alternative explanation to the Earth-centred models' flaws.

Development of Aristarchus Hypothesis.

The only extant work of Aristarchus is called On the Sizes and Distances of the Sun and the Moon and it contains no hint of the heliocentric model. In fact, it adheres to the geocentric view. There are several possibilities for this. It could well be that, for the purpose of the works, it makes no difference which theory is adopted and, therefore, Aristarchus decided that presenting a view in contradiction to the general consensus would have been unwise. Another option would be that he may have arrived at the heliocentric view after writing this work. Some historians who have studied this matter in detail, such as Sir Thomas Heat, believe the latter. In this work, by means of careful geometrical analysis based on the size of the Earth's shadow on the moon during a lunar eclipse, Aristarchus concluded that the Sun must be much larger than the Earth. It is possible that the idea that tiny objects ought to orbit large ones and not the other way around, motivated his revolutionary ideas. Aristarchus also suspected that the stars we see in the night sky are actually nothing more than distant suns.

Unfortunately, Aristarchus works where the heliocentric model is presented are lost. His theories on the universe have been pieced together from later works and references. One of the most important and clear is the one mentioned by Archimedes in his book "The Sand Reckoner":

[...] 'universe' is the name given by most astronomers to the sphere whose centre is the centre of the Earth and whose radius is equal to the straight line between the centre of the Sun and the centre of the Earth. [...] But Aristarchus of Samos brought out a book consisting of certain hypotheses, in which the premises lead to the result that the universe is many times greater than that now so called. His hypotheses are that the fixed stars and the Sun remain unmoved, that the Earth revolves about the Sun in the circumference of a circle, the Sun lying in the middle of the orbit, and that the sphere of the fixed stars, situated about the same centre as the Sun, is so great that the circle in which he supposes the Earth to revolve bears such a proportion to the distance of the fixed stars as the centre of the sphere bears to its surface.
(Archimedes, 1-2)

Rejection of Aristarchus' View

Some historians have suggested that Aristarchus himself may have abandoned his theory as a result of failing to reconcile it with the supposedly circular movements of the heavenly bodies, since all Greek astronomers took for granted that the orbit of all heavenly bodies had to be circular. Whether Aristarchus himself ended up rejecting his own hypothesis is not totally clear. What seems to be clear is that Hipparchus of Nicea, in all probability the greatest astronomical genius of antiquity among Greek astronomers, concluded that the geocentric model better explained the observations than did the model of Aristarchus. The only way that Aristarchus' view could stand mathematical analysis was by supposing an elliptical orbit of the Earth, and this supposition was almost a blasphemy to Greek thought. On top of this, this new model expanded the size of the universe far beyond the accepted size, which was also difficult to accept.

Aristarchus planetary model was discarded only to be rediscovered almost two millennia later during the years prior to the rise of modern science that took place during the Renaissance.

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Aristarchus of Samos (c. 310 - c. 230 BCE) was an ancient Greek mathematician and astronomer from Ionia who came up with a revolutionary astronomical hypothesis. He claimed the Sun, not the Earth, was the fixed centre of the universe, and that the Earth, along with the rest of the planets, revolved around the Sun.

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Books lost to the library
look more into all the people mentioned in this.

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If you invent a time machine, The Library of Alexandria is the first place you should visit (you can see the dinosaurs after, ok?). The most monumental of all ancient learning institutions, the Library was a beacon to the great thinkers of antiquity for over 7 centuries. At its peak, the Library contained nearly one million scrolls: plays by the great Athenian dramatists, annals of Homeric poetry, the schematics of Egyptian mechanics.

And all of it was burned to the ground by zealots.

In honor of this epic shrine to ancient geekery, here are the top five most heartrending and alarmingly forward-thinking losses from the Library, as well as an appeal to all you lovely geniuses reading this to back up your work!

5. Berossus' Babylonaica (written circa 281 BCE): Berossus was an incredibly bright historian whose masterpiece Babylonaica covered the history of the world in three volumes. The first volume describes everything between the creation of the world and the Great Flood, a period Berossus astonishingly estimated as being about 432,000 years! That's over 100 times more than the Old Testament's estimate! Can you imagine the marvelous sights and fantastic events Berossus depicted in this volume? Sadly, as only fragments of the history survived, imagining is in fact all one can do.

4. The works of Sappho (written circa 612-570 BCE): Hardly a scrap of the 9 volumes of Sappho's poetry kept at the Library survived its destruction. But that tiny sliver of her immense genius was still enough to earn her the artistic immortality about which she often wrote (for example, this dagger-in-the-heart of a verse: "Although they are/ Only breath, words/ which I command/ are immortal"). More than a poet, Sappho was perhaps the finest musician of antiquity: her talent was frequently considered proof she was either a tenth muse or a goddess. In one of the most provocative flourishes in history, Stobaeus's Florilegium describes Solon of Athens hearing one of Sappho's songs and asking that it be taught to him. When asked why, he said, "so that I may learn it, then die." That's pretty much the highest praise possible, don't you think?

3. The works of Hero of Alexandria (written circa 10-70 CE): Hero was the greatest experimenter of Greek antiquity. Endowed with mind-boggling mechanical genius, he invented steam engines, wind turbines and hydrostatic fountains millennia before these systems became commonly used. He even created automated machinery, which scholars today see as the groundwork for cybernetics! As if that weren't enough to rest his toga on, he discovered imaginary numbers and probably knew the laws of refraction. Reminder: this is just the stuff we know about Hero. While thankfully, Arab scholars saved a portion of his works, we do not know the bulk of wonders discovered by this brilliant man.

2. The works and life of Hypatia (circa 370-415 CE): In March 415 CE, when the mob led by the ironically named Peter the Reader burned the Library of Alexandria, they also brutally assassinated its last chief librarian, Hypatia. Many scholars view her murder as representing the symbolic death of classical antiquity. And for good reason: Hypatia was a world-renowned mathematician, a fiery lecturer beloved by her thousands of pupils and a woman completely unashamed of outshining her male contemporaries. Literally all of Hypatia's writing was lost with her library, but we know she built hydrometers and astrolabes as well as improving upon the theories of such luminaries of Apollonius, Diophantus and Ptolemy, amongst others.

1. The works of Aristarchus of Samos (circa 310 BCE-230 BCE): This one is the biggest heartbreaker of them all. Sometime in the 3rd Century BCE, Aristarchus of Samos figured out that the Earth orbits the Sun, and not the other way around. He also correctly deduced the order of the planets, and he knew that the solar system was many, many times bigger than his contemporaries' estimates.

WHAT?! Basically, the survival of this book could have saved our species 18 centuries of looking like total idiots for assuming that we are the center of the universe. Think where we would be if, instead of Copernicus taking up the great mantle of heliocentrism in the 15th Century, it was the scientific community of Aristarchus's own time, or Hero's time, or Hypatia's time! We could be taking space-cars to visit our lunar friends, before heading over to Mars for lunch!
What ancient revelations do you think we missed out on from the Library of Alexandria?

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Top Five Most Tantalizing Losses from the Library of Alexandria

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If you invent a time machine, The Library of Alexandria is the first place you should visit (you can see the dinosaurs after, ok?). The most monumental of all ancient learning institutions, the Library was a beacon to the great thinkers of antiquity for over 7 centuries.