The peace was broken in the same year by Hunyadi and king Władysław III of Poland during the Crusade of Varna, which culminated in the Battle of Varna. A crusading army led by Regent John Hunyadi of Hungary was defeated by Sultan Murad II's forces at Kosovo Polje in 1448. This was the last concerted attempt in the Middle Ages to expel the Ottomans from southeastern Europe. Although Hungary was able to successfully defy the Ottomans despite the defeat at Kosovo Polje during Hunyadi's lifetime, the kingdom fell to the Ottomans in the 16th century. Branković also captured Hunyadi at Smederevo for a short time when he was retreating home from Kosovo in 1448, due to their personal feud.