World War I By ChristianR1 Jun 28, 1914 Franz Ferdinand Assassination The Assassination of the Archduke of Austria caused the beginning of World War I Jul 28, 1914 Austria-Hungary declares war on Serbia Apr 22, 1915 First use of gas as a weapon by the Germans May 7, 1915 Sinking of the Lusitania Nov 7, 1916 Wilson re-elected; pledged American neutrality Jan 19, 1917 Zimmermann Note Apr 6, 1917 U.S declares war Nov 7, 1917 Bolsheviks led by Lenin overthrow Russian government Nov 11, 1918 War ends Jun 28, 1919 Treaty of Versailles
