World War I By GabriellaC1 Feb 28, 1914 Archuduke killed Feb 28, 1914 Austria-Hungary declares war on Serbia Jun 28, 1914 Franz Ferdinand Assassination The assassination of the Archduke instigated the beginning of World War I. Apr 1, 1915 First use of gas asa weapon by the Germans May 7, 1915 Sinking of the Lusitania Nov 1, 1916 Wilson reelected; pledged American neutrality Jan 1, 1917 Zimmerman Note Apr 1, 1917 U.S declares war Nov 1, 1917 Bolsheviks led by Lenin overthrow Russian government Nov 11, 1918 War ends Jun 28, 1919 Treaty of Versailles
