He was the heir to the Austrian throne and was assassinated by a Serbian nationalist. This caused Austria-Hungary to declare war on Serbia.

Franz Ferdinand did not expect to ascend to the throne himself, but Crown Prince Rudolf committed suicide in 1889, which made his father the next in line to be emperor.

He indirectly started off WW1 by assassinating Archduke Franz Ferdinand, the heir to the Austrian throne.

Gavrilo Princip worked with six other people to plan and execute the killing.

In October 1917, during WW1, he began a revolution where the new Russian government was driven from power and a Communist government was put in its place.

Vladimir Lenin chose "The Internationale" to serve as the anthem of the new Communist state in 1918.

He was the kaiser of the German Empire and when the war started in August, 1914, the leaders in Britain, France, and Russia blamed him and German imperial expansionism for the war.

Many people in Allied countries referred to him as "Kaiser Bill" and thought of him as the leader of "barbarian hunters."

He took direct command and control of the Russian armies against the advice of his ministers during WW1. He was the last Russian emperor.

He, his wife, Alexandra, and their children were killed by the Bolsheviks.

Clemenceau lead France through WW1 and as leader of the French delegation at the Paris Peace Conference, he played a major role in drafting the Treaty of Versailles and figuring out conference policies.

He taught French in a girls' academy at Stamford, Connecticut and married one of his pupils, Mary Plummer. They had two daughters and one son but separated after 7 years.

He was the figurehead and leader of the British Empire. He and his wife, Queen Mary, supported both the armed forces and the civilian populations through hundreds of official visits and their own family's service and self-sacrifice throughout the war.

George V became the first monarch in British history to have his voice broadcast into people's houses, when he broadcasted the first Christmas speech.

He did not want more British troop to die in the trenches at the Western Front so he made a plan that would begin with the invasion of the Gallipoli Peninsula in Turkey. However, the plan was disastrous and more than forty-five thousand Allied troops were killed in the attack and the British were forced to abandon the effort.

When WWI began, he was named First Lord of the Admiralty, the civilian leader of the British Royal Navy.

He was the 28th president of the United States from 1913-1921 and led the U.S. through World War 1.

He led the Paris Peace Conference in 1919 to make the League of Nations part of the peace treaty with Germany after the war.

He was commander in chief of the American Expeditionary Force in Europe during WW1 in support of the Allies.

Pershing graduated from West Point in 1886 with an outstanding record.

He was a French Marshall and he was commander in chief of the Allied armies in WWI.

In the spring of 1918, when the Allies were threatened by the German grand offensive he stopped the Germans and launched a counteroffensive which drove them back and ended the war.

He was a British general and commanded British forces on the Western front in Europe during WWI.

He is credited with the final British victories over the German armies in 1918 when the war was ending.