A peninsula of southeast Europe bounded by the Black Sea, the Sea of Marmara, and the Aegean, Mediterranean, Ionian, and Adriatic Seas. Formerly part of the Roman and Byzantine empires, the region fell to the Ottoman Turks by 1500. The Balkan Wars (1912-1913 and 1913), treaties signed after World War I, and nationalist movements in the early 1990s led to the present country boundaries.