Bayezid I defeated the crusaders at the Battle of Nicopolis in 1396. The battle took place on 25 September near Nicopolis, a major fortress on the Danube in what is now Bulgaria. The crusading army included forces from Hungary, France, Burgundy, the Holy Roman Empire, Venice, and several other European powers. Its aim was to drive back Ottoman expansion in the Balkans.
Bayezid, who had ruled the Ottoman Empire since 1389, moved rapidly to relieve the besieged fortress. The crusaders attacked before their commanders had fully coordinated their forces. French and Burgundian knights advanced successfully at first, but became separated from the main army and were surrounded by Ottoman troops and Serbian allies. The Ottoman victory was decisive: many crusaders were killed or captured, and numerous prisoners were later executed.
A common mix-up is to confuse Bayezid with Mehmed II, who conquered Constantinople in 1453, or Murad I, Bayezid’s predecessor. Nicopolis strengthened Ottoman control in the Balkans and discouraged further large European coalitions. Bayezid was later defeated and captured by Timur at Ankara in 1402, temporarily throwing the Ottoman state into civil war.