After the death of Sultan
Murad II and the
conquest of Istanbul, the Serbian despot
Đurađ Branković sent a delegation to the
Ottoman ruler Mehmed II who at the time was in
Edirne. Mehmed was presented with the keys to some Serbian castles that had formerly belonged to the Ottomans, as well as being congratulated for his success in taking Constantinople. At the same time, with the encouragement of the
Pope, the Despot was in negotiations with the
Hungarians to participate in a new
Crusade, which was intended to be against the Ottomans. The Ottomans learned about the Hungarian contacts of the Serbian despot aimed against them through their spies and prepared to retaliate accordingly. After the Ottoman court asked the Serbian delegation for the keys to other castles which had belonged to the Ottomans but were passed onto the Serbs, they were refused. Thereupon, a campaign against Serbia was made in the spring of 1454. == Battle ==