The great landmass of Anatolia was between the Ottoman army's headquarters in Istanbul and many of the theatres of war. The Ottoman Empire started military action after three months of formal neutrality, but it had signed a secret alliance with the Central Powers in August 1914. Following the attack, Russia and its allies (Britain and France) declared war on the Ottomans in November 1914. The Ottoman entry into World War I began on 29 October 1914 when it launched the Black Sea Raid against Russian ports. Main article: Middle Eastern theatre of World War I