Turkey (Türkiye ), officially the Republic of Turkey (Türkiye Cumhuriyeti ), is a transcontinental country located mainly in Western Asia, with a smaller portion on the Balkan Peninsula in Southeast Europe. East Thrace, located in Europe, is separated from Anatolia by the Sea of Marmara, the Bosphorous strait and the Dardanelles (collectively called the Turkish Straits). Turkey is bordered by Greece and Bulgaria to its northwest; Georgia to its northeast; Armenia, the Azerbaijani exclave of Nakhchivan and Iran to the east; and Iraq and Syria to the south. Istanbul is the largest city, but more central Ankara is the capital. Approximately 70 to 80 per cent of the country's citizens identify as Turkish. Kurds are the largest minority; the size of the Kurdish population is a subject of dispute with estimates placing the figure at anywhere from 12 to 25 per cent of the population.
At various points in its history, the region has been inhabited by diverse civilizations including the Assyrians, Greeks, Thracians, Phrygians, Urartians, and Armenians. Hellenization started during the era of Alexander the Great and continued into the Byzantine era. The Seljuk Turks began migrating into the area in the 11th century, and their victory over the Byzantines at the Battle of Manzikert in 1071 symbolizes the start and foundation of Turkey. The Seljuk Sultanate of Rûm ruled Anatolia until the Mongol invasion in 1243, when it disintegrated into small Turkish principalities. Beginning in the late 13th-century, the Ottomans started uniting these Turkish principalities. After Mehmed II conquered Constantinople in 1453, Ottoman expansion continued under Selim I. During the reign of Suleiman the Magnificent the Ottoman Empire encompassed much of Southeast Europe, West Asia and North Africa and became a world power. In the following centuries the state entered a period of decline with a gradual loss of territories and wars. In an effort to consolidate the weakening social and political foundations of the empire, Mahmut II started a period of modernisation in the early 19th century, bringing reforms in all areas of the state including the military and bureaucracy along with the emancipation of all citizens.