The Ottoman Empire joined World War I ( 1914 – 1918 ) on the side of the Central Powers and was ultimately defeated . The deportation of Armenian intellectuals on 24 April 1915 was among the major events which marked the start of the Armenian Genocide during WWI . As a result of the war and the events in its aftermath , the city 's Christian population declined from 450,000 to 240,000 between 1914 and 1927 . The Armistice of Mudros was signed on 30 October 1918 and the Allies occupied Constantinople on 13 November 1918 . The Ottoman Parliament was dissolved by the Allies on 11 April 1920 and the Ottoman delegation led by Damat Ferid Pasha was forced to sign the Treaty of Sèvres on 10 August 1920
Armenian Genocide
Armenian Genocide
Istanbul