World War 1

Archduke Ferdinand's Assassination

Jun 28, 1914

Austria-Hungary Declares War on Serbia

Jul 28, 1914

A-H makes demands, Serbia does not comply, A-H declares war because of this.

Germany Declares War on Russia

Aug 1, 1914

Germany Declares War on France

Aug 3, 1914

Poison Gas

Apr 15, 1915

First used by the Germans

Submarine Warfare

May 7, 1915

German U-Boat torpedoes A British passenger liner, Lusitania. 1000 people die. Leads to creation of Sussex pledge.

Armored Tank

Jan 15, 1916

First used by Allies

Germany Reverses Policy on Submarine Warfare

Jan 15, 1917

Germany would sink all vessels heading to allied ports.

Zimmerman Telegram Published

Mar 1, 1917

Telegram from Germany to Mexico intercepted by British, published in newspapers on March 1, 1917.

America Joins the Fight

Apr 6, 1917

President Wilson asks congress for a declaration of war on Germany. Made official on April 6.