World War I By diamond_badd121 Period: Jan 1, 1914 to Dec 31, 1918 World War I Jun 28, 1914 June 28th - the assassination of Francis Ferdinand . June 28th - the assassination of Francis Ferdinand . Jul 18, 1914 • July 18th Austria declared war on Serbia Aug 1, 1914 • August 1st - Germany declares war on Russia. Aug 4, 1914 August 4th - Britain and allied countries such as Australia Declares war on Germany two sides formed the allied powers and the central powers . May 3, 1915 • May 3rd - Italy changed sides and declared war on Germany and Austria Jul 1, 1915 • July 1st - start of the battle of Somme. Jan 27, 1916 • January 27th - conscription introduced in Britain. Apr 29, 1916 • April 29th - British forces surrender in Mesopotamia . Dec 23, 1916 • December 23rd - the allies started evacuation from Gallipoli Apr 6, 1917 • April 6th - US declared war. Jul 15, 1917 July 15th - Second battle Marne Nov 6, 1917 • Nov. 6th - The British launched assault on the western front. Nov 11, 1917 November 11th - Germany signed armistice with allies officially ending the war. Dec 5, 1917 Dec. 5th Armistice between Germany and Russia signed. Mar 21, 1918 • March 21st - Germany broke through Somme.