Ottomanism remained a strong current of thought in the early twentieth century. The sultans harsh regime was hated and many alliances formed against it from within the empire. The strongest of these, the Committee of Union and Progress (CUP) headed by Mustafa Kemal (also known as Atatürk), led a military revolt in 1908 calling for a restoration of the 1876 constitution. The sultan agreed to hold parliamentary elections in which the CUP won all but one of the seats. The government was extremely unstable however due to in-fighting between liberals and nationalists and non-Turkish communities demanding more independence.
Europe used the opportunity to seize land from the empire. In 1911, Italy declared war and won Libya. A secret union of Greece, Serbia, Montenegro and Bulgaria invaded the empire in 1912 and reduced the empire's entire European territory to part of Eastern Thrace. The liberal government in power since 1912 was overthrown in 1913 by the most authoritarian groups of the Young Ottoman movement including Atatürk. In June 1913, under the new military leader Enver, Ottoman forces seized Bulgaria while the other Balkan nations were busy fighting over previously won territories.
On August 2, 1914, Enver signed a treaty with Germany which pitted them against France, Britain and Russia in the first World War. The Ottoman army was all but destroyed in its 1914-15 offensive against the Russians. Some Armenians took part in the fighting on the side of the Russians and Enver declared that their was an imminent Armenian uprising. With that, Turkish troops preceded to systematically slaughtered over one million Armenians in the first holocaust of the twentieth century.
British forces launched attacks between 1915 and 1917 but all were successively put down by Atatürk, but Russian forces gained the eastern territory Erzincan in 1916. The Russians returned this land, however, when they left the war in 1918 following the Bolshevik Revolution.
Sharif Husayn ibn Ali, the sultan's regent in Mecca and western Arabia, led the Arab Revolt of 1916. In 1917, British forces in Egypt invaded Palestine; they controlled Jerusalem by December. By October 18, British forces made it all the way to Damascus. Atatürk withdrew and signed a peace agreement.
