Ottoman Emperor Bayezid I defeats a Christian army at the Battle of Nicopolis.

The Battle of Nicopolis took place on 25 September 1396 and resulted in the rout of an allied Crusader army at the hands of an Ottoman force, raising 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 big Crusades of the Middle Ages, together with the Crusade of Varna in 1443–1444. By their victory at Nicopolis, the Turks discouraged the formation of European coalitions against them. They maintained their pressure on Constantinople, tightened their control over the Balkans, and became a greater threat to Central Europe.