A battle between Crusaders and Ottoman forces. The town of Nicopolis, on the River Danube was besieged by a force of Crusaders under Sigismund of Hungary and John, son of Philip the Bold of Burgundy. A combined force of Hungarians and European knights had answered an appeal to relieve Constantinople from Turkish attack. After initial success, they were confronted by the Turks under Sultan Bajazet I (ruled 1389–1402). The Crusaders were defeated and many of the knights were executed after the battle, although Sigismund himself escaped.