World War I (1914-1918)
A global war conducted between 1914 and 1918, in which the Allied Powers, led by Britain, France, Japan, Russia (to 1917) and the United States (from 1917), fought the Central Powers, led by the German, Austro-Hungarian and Ottoman Empires. In the Middle East, the war concluded with the British and French occupying most of the southern part of the Ottoman Empire, including modern-day Iraq, Syria, Lebanon, Jordan, Israel and the Palestinian Territories. During the war, several conflicting arrangements as to the political future of the Ottoman-controlled Middle East were concluded: the McMahon-Hussein Letters, the Sykes-Picot Agreement and the Balfour Declaration. Following the end of the war with the Armistice of November 1918, the Paris and San Remo Conferences established the mandate system, dividing control of the aforementioned Ottoman territories between Britain and France. The war in the Middle East officially ended with the Treaty of Lausanne in 1923 between the Allies and Turkey, heir to the defunct Ottoman Empire.