1. Key Players: Military in Austria-Hungary Archduke Franz Ferdinand
Heir to the Austria-Hungarian throne
Assassination considered the start of the first world war.
Franz-Josef the ruler of Austria-Hungary at the time declared war on Serbia three weeks after the assassination. He believed that It was Serbians that had killed is son Franz Ferdinand.

2. Military in Austria-Hungary and Germany
Franz Conrad Von Hoetzendorf was the Austrian Military general at the time. He played a crucial in convincing Franz-Joseph to wage war. He also led Austria-Hungarian troops during the war.
Leopold Berthold was the wartime Minister of Foreign Affairs for Austria-Hungary During the war. He Secured support from German Emperor Wilhelm II before the war.
He also aided in persuading Franz-Joseph to go to war by lying to him that Serbia had attacked first.

3. Military in The United States of America and Russia
Emperor Nikolaus II
His leadership of Russia was marked by multiple political errors. He promised to back Serbia. Led the war himself for Russia. Later executed by Lenin, and is now a Saint of the Russian Orthodox Church
Woodrow Wilson
President of the United States during the war. Kept his country out of the war until Germany began using submarine warfare in He won the Nobel Peace Prize for ending the war in 1918.

4. Military in Canada
Robert Borden Prime Minister of Canada during the war. Beat out Laurier in the Election of Signed up Canada to aid the British during the war. Later supported conscription.
Sam Hughes Minister of war during WW1. In charge of the recruitment of soldiers. Known to have discriminated against French Canadians willing to recruit at the start of the war. Part of the Orange Order, therefore extremely anti-Catholic. Forced French Canadians to speak English during training

5. Military in Britain and France
David Lloyd George was the wartime Prime Minister of Britain. Part of a coalition government as a liberal. Fully supported the war from the beginning with a conscription
Ferdinand Foch the French general, and later, towards the end of the war was made the Commander of the Allies.
Georges Clemenceau Led France during the final year of the war and was a driving force behind the treaty of Versailles.