The Battle of Nicopolis (Bulgarian: Битка при Никопол, Bitka pri Nikopol; Turkish: Niğbolu Savaşı, Hungarian: Nikápolyi csata, Romanian: Bătălia de la Nicopole) took place on 25 September 1396 and resulted in the rout of an allied crusader army of Hungarian, Croatian, Bulgarian, Wallachian, French, English, Burgundian, German and assorted troops (assisted by the Venetian navy) at the hands of an Ottoman force, raising of the siege of the Danubian fortress of Nicopolis and leading to the end of the Second Bulgarian Empire. It is often referred to as the Crusade of Nicopolis as it was one of the last large-scale Crusades of the Middle Ages, together with the Crusade of Varna in 1443–1444.
There were many minor crusades in the 14th century, undertaken by individual kings or knights. Most recently there had been a failed crusade against Tunisia in 1390, and there was ongoing warfare in northern Europe along the Baltic coast. After their victory at the Battle of Kosovo in 1389, the Ottomans had conquered most of the Balkans, and had reduced the Byzantine Empire to the area immediately surrounding Constantinople, which they later proceeded to besiege (in 1390, 1395, 1397, 1400, 1411, 1422 and finally conquering the Byzantine capital in 1453).