Anatolia (Turkey in Asia) was occupied in about 1900 B.C. by the Indo-European Hittites and, after the Hittite empire's collapse in 1200 B.C., by Phrygians and Lydians. The Persian Empire occupied the area in the 6th century B.C., giving way to the Roman Empire, then later the Byzantine Empire. The Ottoman Turks first appeared in the early 13th century, subjugating Turkish and Mongol bands pressing against the eastern borders of Byzantium and making the Christian Balkan states their vassals. They gradually spread through the Near East and Balkans, capturing Constantinople in 1453 and storming the gates of Vienna two centuries later. At its height, the Ottoman Empire stretched from the Persian Gulf to western Algeria. Lasting for 600 years, the Ottoman Empire was not only one of the most powerful empires in the history of the Mediterranean region, but it generated a great cultural outpouring of Islamic art, architecture, and literature.

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.

Turkey invaded Cyprus by sea and air on July 20, 1974, following the failure of diplomatic efforts to resolve conflicts between Turkish and Greek Cypriots. Turkey unilaterally announced a cease-fire on Aug. 16, after having gained control of 40% of the island. Turkish Cypriots established their own state in the north on Feb. 13, 1975. In July 1975, after a 30-day warning, Turkey took control of all the U.S. installations except the joint defense base at Incirlik, which it reserved for “NATO tasks alone.”