World War I

The Ottoman Empire joined Germany and Austria (the Central Powers) during World War I (1914-1918) and collapsed after their defeat. The YoungTurks who controlled the government, anxious to have an all-Muslim empire, saw the chance to get rid of the Christian Armenians. Evacuations and killings during the Armenian genocide of 1915 left 600,000 dead and eliminated all the Armenians inside Turkey.
The British expected easy victories, and sent armies into Mesopotamia (Iraq), which were badly defeated, and landed at Gallipoli in order to capture Istanbul, but failed badly in 1915. However, the British were successful in moving from Egypt to conquer Palestine, using the aid of Arab nationalists stirred up by British officer Lawrence of Arabia (T.E. Lawrence).
Winston Churchill and other top British leaders envisioned an operation in which they placed their strength against Ottoman weakness. Instead of engaging a feeble opponent, however, the British faced the best-trained and best-led divisions in the Ottoman army and were up against the most heavily fortified and well-prepared positions in the Ottoman Empire. In command and control the Ottoman army performed well at all levels, and Ottoman soldiers proved to be effective fighters on the defensive. The Germans, furthermore, provided very talented generals and senior staff members to aid and help direct the Ottoman effort. As a result the Ottoman army fought the British to a stalemate, leading the British to abandon the campaign.[1]
The secret wartime Sykes-Picot Agreement in 1916 was a plan for Russian, British, and French administration of dismembered Ottoman lands in the Middle East and Central Asia. Russia dropped out but at the 1919 Paris Peace Conference much of the territory of the Ottoman Empire was placed under British and French control, while Mustafa Kemal Ataturk led a revolution and established the secular nation of Turkey.
Reconstruction of Turkey
After the reign of Sultan Süleyman I the Magnificent (1494–1566), the Ottoman Empire began to decline politically, administratively, and economically. By the 18th century, Russia was seeking to establish itself as the protector of Christians in Turkey's Balkan territories. Russian ambitions were checked by Britain and France in the Crimean War (1854–1856), but the Russo-Turkish War (1877–1878) gave Bulgaria virtual independence and Romania and Serbia liberation from their nominal allegiance to the sultan. Turkish weakness stimulated a revolt of young liberals known as the Young Turks in 1909. They forced Sultan Abdul Hamid to grant a constitution and install a liberal government. However, reforms were no barrier to further defeats in a war with Italy (1911–1912) and the Balkan Wars (1912–1913). Turkey sided with Germany in World War I, and, as a result, lost territory at the conclusion of the war.

Turkey's current boundaries were drawn in 1923 at the Conference of Lausanne, and Turkey became a republic with Kemal Atatürk as the first president. The Ottoman sultanate and caliphate were abolished, and modernization, reform, and industrialization began under Atatürk's direction. He secularized Turkish society, reducing Islam's dominant role and replacing Arabic with the Latin alphabet for writing the Turkish language. After Atatürk's death in 1938, parliamentary government and a multiparty system gradually took root in Turkey, despite periods of instability and brief intervals of military rule. Neutral during most of World War II, Turkey, on Feb. 23, 1945, declared war on Germany and Japan, but it took no active part in the conflict. Turkey became a full member of NATO in 1952, was a signatory in the Balkan Entente (1953), joined the Baghdad Pact (1955; later CENTO), joined the Organization for European Economic Cooperation (OEEC) and the Council of Europe, and became an associate member of the European Common Market in 1963.