However, the victory at Rovine sparked a great crusade in which forces from England, France, Germany, and other European countries joined Hungarian king Sigismund and Mircea I with the Venetian fleet which was to enter the Danube from the Black Sea and support the army on the mainland. Crusader forces gathered in Hungary, after which they crossed the Danube and took Vidin. After that, the march continued down the Danube. Nicopolis, which had a large Ottoman garrison was besieged. The siege broke the blockade of Constantinople, forcing Bayezid to send troops towards the Danube, joining forces with Stefan Lazarević's heavy cavalary near Plovdiv. A great battle took place on 25 September 1396 in which the Crusader forces were completely destroyed. Although numerically very large, the Crusader army lacked a joint command and thus poorly coordinated on the battlefield, and an important factor was the complete ignorance of the Ottoman army's war methods. After initial Crusader success, the Ottomans went on a counterattack that stopped with the entry of Hungarian knights in battle, which began to suppress them. In this turning point of battle the Serbian heavy cavalry led by Stefan Lazarević himself broke through Hungarian lines and surrounded the King Sigmund and attacked the Hungarian banner troops of Nicholas II Garay. Garay's troops were dispersed, which had a decisive influence on the course of the battle, because some of the Crusaders thought that Sigismund had died and that the battle was lost, while the Hungarian commanders convinced Sigismund that the battle was practically lost and that it was better to withdraw. After that Crusader orders fell apart and was followed by carnage. One of the participants in the battle, Johann Schiltberger, described the Serbian attack