Hunyadi succeeded during the Siege of Belgrade in 1456 against the Ottomans, the biggest victory against that empire in decades. This battle became a real Crusade against the Muslims, as the peasants were motivated by the Franciscan monk Saint John of Capistrano, who came from Italy predicating Holy War. The effect that it created in that time was one of the main factors that helped in achieving the victory. However the premature death of the Hungarian Lord left Pannonia defenseless and in chaos. In an extremely unusual event for the Middle Ages, Hunyadi's son, Matthias, was elected as King of Hungary by the nobility. For the first time, a member of an aristocratic family (and not from a royal family) was crowned.
Who didn't the Hungarian nobility elect as King of Hungary?