The Great War By moneim143 Jun 28, 1914 Assassination of Archduke Franz Ferdinand of Austria Jul 5, 1914 Austria-Hungary seeks German support for a war against Serbia in case of Russian militarism. Jul 28, 1914 Austria-Hungary declares war on Serbia. Russia mobilizes Aug 1, 1914 Germany declares war on Russia Aug 6, 1914 Austria-Hungary declares war on Russia.Serbia declares war on Germany. Aug 23, 1914 Japan declares war on Germany. Nov 1, 1914 Russia declares war on the Ottoman Empire. Aug 27, 1916 Italy declares war on Germany. Apr 6, 1917 The United States of America declares war on Germany Jul 18, 1919 Treaty of Versailles between the Allies and Germany