Turkey, officially the Republic of Turkey, is a transcontinental country straddling Southeastern Europe and Western Asia. It is bordered on its northwest by Greece and Bulgaria; north by the Black Sea; northeast by Georgia; east by Armenia, Azerbaijan, and Iran; southeast by Iraq; south by Syria and the Mediterranean Sea; and west by the Aegean Sea. Istanbul, which straddles Europe and Asia, is the country's largest city, while Ankara is the capital. Approximately 70 to 80 percent of the country's citizens are ethnic Turks, while the largest minority are Kurds at 20 percent.
One of the world's earliest permanently settled regions, present-day Turkey was home to important Neolithic sites like Göbekli Tepe, and was inhabited by ancient civilisations such as the Hattians and Anatolian peoples. Hellenization started in the area during the era of Alexander the Great and continued into the Byzantine era. The Seljuk Turks began migrating in the 11th century, and the Sultanate of Rum ruled Anatolia until the Mongol invasion in 1243, when it disintegrated into small Turkish principalities.