Potidaea fell to Athens after the 3 year siege

Thebes, a Peloponnesian ally, attacked Platea, an Athenian ally. This broke the 446 30 year peace and it was thus an old rivalry renewed that saw the first fighting of the war. The Thebans took the city but were then defeated in a counter-attack. The Plataeans then executed their Theban captives.

Plataea was then attacked and finally besieged by the Spartans and their allies and after a siege of over 2 years the city fell. The Spartans, under pressure from their Theban allies, executed all who had opposed them, and the city was razed.

The Athenians blocked the entrance to the Corinthian Gulf and then beat the Peloponnesians in naval battles off Naupactus. Athens had secured dominance at sea.

Within this year, Mytilene, a town on Lesbos, revolted from Athens and joined the Peloponnesian League. It had been one of only two remaining ship providing allies. The Athenians were so angry about the revolt that they voted for a motion put forward by Cleon (who is presented as the leading demagogue of his day) that the entire adult male population of Mytilene should be put to death.

The day after, a second vote was held, and it was agreed not to kill the entire population. This reversal of policy after shows the different attitudes towards allies in Athens.

The first annual Spartan invasion of Attica achieved little. Just after the second invasion of 430, the plague hit Athens and lasted for two years. The effects were made worse by the fact that evacuees from the countryside were crammed into the city.

Summer heat, as well as lack of water and sanitation, caused the disease to spread and immunity did increase among the survivors, but by the end, 4,400 of Athens' 13,000 hoplites were dead.

Thucydides states that the plague was terribly damaging for Athens. He also argues that Athens not only lost valuable men, but also vital leadership as Pericles died in the plague. He continued to argue that the Athenian leaders who followed Pericles (Cleon, for example) were not of the came calibre.

By 426, and after five years of war, Athens was short of money

Within this year the Peloponnesians sent an embassy to Persia in an attempt to gain Persian help. However, the envoys were executed when caught in Thrace.

The Athenian general Demosthenes fortified a place near Pylos on the Peloponnese as he was hoping to encourage helots to desert. This caused the Spartans to abandon the raid on Attica in which they were engaged. The Athenians were taking the war to the Peloponnesians. It was a change in policy from Pericles' defensive strategy on land. Athens then gained a victory at Pylos which was a result of hundreds of Lacedaemonians being cut off on the island of Sphacteria nearby. In response, the Spartans sought an armistice while envoys were sent to Athens to conclude a lasting peace on terms that would protect Spartan dignity. The Athenian generals at Pylos granted the armistice but in Athens the peace deal was not approved as Cleon urged the Athenian assembly to ask for better terms. The Spartan envoys’ case basically suggested that Athens had been fortunate at Pylos, and finding themselves the beneficiary of fortune, the Athenians could best capitalise on their current position by making peace on terms agreeable to both sides. The implication is that Athens had suffered some setbacks with the plague and raids on its territory; it now had the chance to make a favourable peace that would win it the praise of all Greeks. The Spartan envoys even hold out the prospect of Athens and Sparta working together to enjoy hegemony over all other Greeks. Despite this, the Athenian Assembly did not accept the offer of Peace and it is implied that many Athenians would have been open to a fair peace deal, but they were greatly influenced by Cleon. The Spartans were said to have been prepared to negotiate further but that Cleon had prevented this by arguing that all negotiation should be with the whole Assembly so that no secret deals could be done. And so, the Spartans chose to not risk making significant concessions in front of the Assembly in case they lost face, thus giving up. As winter approached the Athenians realised they couldn’t continue blockading the island. Many Athenians now regretted not accepting Sparta’s peace offer. This led to disagreements between the general Nicias and Cleon. Nicias offered to give up his command if Cleon thought he could do a better job. Following this, the Athenians (under the direction of Cleon) then attacked the island with archers, javelin throwers and hoplites, resulting in the Lacedaemonians eventually surrendering. 292 Lacedaemonians, including 120 Spartiates, were captured on the island of Sphacteria near Pylos, shocking the Spartans as they had broken a Spartan value (to rather die than surrender). These prisoners were taken to Athens as hostages to guard against further Peloponnesian attacks on Attica, with the Spartans not able to risk attacking Attica due to their men being held as hostages.  (Thucydides)

A bronze hoplite shield found in Athens offers support for Thucydides’ account. The shield carries an inscription stating it was taken from one of the 292 Lacedaemonians captured at Pylos.

Due to suffering setbacks within the Peloponnese, the Spartans sent the general Brasidas north to Thrace with a force of helots and Peloponnesian mercenaries to continue the conflict on a different front. Brasidas enjoyed success in persuading cities there to revolt against Athens. Many cities were persuaded by him due to his fair and moderate conduct towards them and even resulted in other cities in the region to revolt due to his influence. Brasidas took the city using a mix of treachery, hostages and persuasion (he offered moderate terms to persuade the inhabitants to open their gates – the inhabitants could keep their property and citizenship). The inhabitants of nearby Argilus helped in the plot as they too wished to revolt against Athens and also wished to gain influence over Amphipolis. Brasidas’ allies in Amphipolis encouraged the inhabitants to take his offer: they did. The fair and moderate terms encouraged other cities to revolt from Athens, as did Athens’ recent defeat at Delium in Boeotia further south and Brasidas’ propaganda about Athenian weakness. Athens responded to the threat of further cities revolting by sending soldiers to garrison them. Brasidas responded to this challenge by asking for reinforcements from Sparta. The Spartans did not, however, immediately send reinforcements, partly because other Spartan nobles envied Brasidas’ growing reputation, partly because they were more concerned to get their men back from Athens and end the war. Brasidas, however, followed up his success at Amphipolis by taking the nearby town of Torone. He defeated the Athenian garrison stationed there with the help of some local rebels. (Thucydides)

Aristophanes adds support for suggestion that Athenian allies resented the tribute levied on them and were ready to revolt. (Aristophanes)

Demosthenes and Hippocrates (Athenian generals) attempt to reestablish Athens' land empire in central Greece (First Peloponnesian War) by supporting Boeotian rebels in establishing democracies. Demosthenes was the driving force behind this policy. A major hoplite battle took place at Delium, but the plan failed and Athens suffered a major defeat)

Sparta could use its newfound influence in Thrace to bargain with Athens over the release of the men captured on Sphacteria. This benefit became apparent soon after the capture of Amphipolis and Torone. The Athenians had also been recently defeated by the Boeotians at Delium in Boeotia. The Athenians had allied with Boeotian rebels in an attempt to instigate democratic revolutions in the cities of Boeotia. But the plan failed and they suffered a significant setback at Delium where they were defeated. As a consequence of this overall situation, the Spartans and Athenians made an armistice for a year. The Athenians hoped to gain the time necessary to prevent Brasidas being able to encourage any more cities to revolt against them. The Spartans hoped that the lull in the fighting would persuade the Athenians of the benefits of making a more general and long-lasting peace. Sparta would then get its men back from Athens. The Spartans wanted a peace urgently while Brasidas had given Athens cause for concern. They realised that Athens might easily restore the situation in Thrace and Chalcidice to her favour in the near future and so wanted peace quickly before this could happen and Athens demanded more for any deal. (Thucydides)