Key Events and Treaties of World War I

Assassination of Archduke Franz Ferdinand

Triggered the start of WWI on June 28, 1914.

Austria-Hungary declaration of war on Serbia

Occurred on July 28, 1914.

Germany declaration of war on Russia

Occurred on August 1, 1914.

Germany declaration of war on France

Occurred on August 3, 1914.

Britain declaration of war on Germany

Caused by Germany's invasion of Belgium on August 4, 1914.

Russia declaration of war on Austria-Hungary

Occurred on August 6, 1914.

First Battle of Marne

A major Allied victory in September 1914 that stopped the German advance into France.

Ottoman Empire entry into WWI

Allied with Central Powers in late 1914.

Italy joining the Allies

Occurred in May 1915.

Second Battle of Ypres

Significant for the first use of poison gas by Germany in April 1915.

Battle of Gallipoli

Failed Allied invasion of the Ottoman Empire; major defeat in 1915.

Battle of Verdun

Significant for being the longest battle of WWI, with ~700,000 casualties (Feb-Dec 1916).

Battle of the Somme

One of the bloodiest battles, with over 1 million casualties (July-Nov 1916).

Germany's policy of unrestricted submarine warfare

Attacking all ships, including civilian, around Britain; resumed in early 1917.

Zimmermann Telegram

A German proposal to Mexico to join war against the U.S.; intercepted and published by Britain in March 1917.

U.S. declaration of war on Germany

Occurred on April 6, 1917.

February Revolution in Russia

Tsar Nicholas II abdicated in March 1917.

Treaty of Brest-Litovsk

Ended Russia's involvement in WWI on March 3, 1918.

Ludendorff Offensive

Germany's final push on the Western Front in Spring 1918.

Second Battle of the Marne

Significant as a turning point where the Allied counter-offensive began in July 1918.

Germany armistice agreement

Occurred on November 11, 1918 - war ends.

Paris Peace Conference

Began in January 1919 to negotiate peace treaties.

Treaty of Versailles

Officially ended the war with Germany, signed on June 28, 1919.

Requirements of the Treaty of Versailles for Germany

Accept guilt for war, pay reparations, limit military, and give up territory.

Treaty of Versailles effect date

Took effect on January 10, 1920.

U.S. ratification of the Treaty of Versailles

The Senate rejected it in March 1920 due to opposition to the League of Nations.

U.S. action instead of joining the Treaty of Versailles

Signed a separate peace treaty with Germany, Austria & Hungary in August 1921.