Timeline for World War One By Yoyo12 Jun 28, 1914 Archduke Franz Ferdinand is Assassinated Jul 23, 1914 Austria's Ultimatum to Serbia Jul 28, 1914 Austria declares War on Serbia Aug 4, 1914 Britain declares war of Germany Aug 26, 1914 Battle of Tannenberg begins Sep 6, 1914 First Battle of the Marne Begins Oct 1, 1914 German U-Boat warfare begins Oct 24, 1914 Russian Communist Revolution begins Nov 1, 1914 Trench Warfare Begins Jan 18, 1915 Japan presents the Twenty-one Demands to China Apr 23, 1915 Battle of Gallipoli May 7, 1915 Sinking of the Lusitania May 23, 1915 Italy joins the Allies Feb 21, 1916 Battle of Verdun begins May 31, 1916 Battle of Jutland begins Jul 1, 1916 Battle of the Somme Jan 19, 1917 Zimmerman Note discovered Feb 1, 1917 Unrestricted U-boat resumed Apr 6, 1917 America Enters the War Mar 3, 1918 Treaty of Brest-Litovsk signed Sep 26, 1918 Meuse-Argonne Offensive begins Nov 9, 1918 Kaiser Wilhelm abdicates Nov 11, 1918 The Armistice is signed Nov 15, 1918 Hindenburg Offensive begins Jun 28, 1919 Treaty of Versailles ends the war