Nikopol (nēkôˈpôl) [key], town (1993 pop. 4,897), N Bulgaria, a port on the Danube River bordering Romania. Farming, viticulture, and fishing are the chief occupations. Founded in 629 by Byzantine emperor Heraclius, Nikopol (then Nicopolis) became a flourishing trade and cultural center of the second Bulgarian kingdom. In 1396 at Nikopol the Ottoman Turks under Beyazid I defeated an army of crusaders led by King Sigismund of Hungary (later Emperor Sigismund). The Turkish victory removed the last serious obstacle to a Turkish advance on Christian Europe. However, when Timur defeated Beyazid (1402), Europe gained a respite. The Turks strongly fortified Nikopol, which was strategically important during the Russo-Turkish wars (18th–19th cent.), but the city later declined.