World War 1 By Rii Aug 3, 1914 (EU) Germany Attacks/Declares war on France Sep 3, 1914 (EU) Britian Declares War On Germany Dec 25, 1914 (EU)Christmas Truce of 1914 May 7, 1915 (US) Sinking of the Lusitania Period: Mar 14, 1916 to Jan 7, 1917 US chases Pancho Villa Period: Jul 1, 1916 to Nov 18, 1916 Battle of the Somme Nov 7, 1916 (US)Election of 1916 Apr 2, 1917 US Woodrow Wilson asks congress for a declaration of war. Wilson asked for war because president technically can't declare war. Apr 6, 1917 (US) United states declares war on Germany. Congress approves war and the united states declares it.