The Ottomans successfully defended the Dardanelles strait during the Gallipoli campaign (1915–1916) and achieved initial victories against British forces in the first two years of the Mesopotamian campaign, such as the Siege of Kut (1915–1916); but the Arab Revolt (1916–1918) turned the tide against the Ottomans in the Middle East. In the Caucasus campaign, however, the Russian forces had the upper hand from the beginning, especially after the Battle of Sarikamish (1914–1915). Russian forces advanced into northeastern Anatolia and controlled the major cities there until retreating from World War I with the Treaty of Brest-Litovsk following the Russian Revolution in 1917.