On 22 July 1456, the forces of the Hungarian nobleman John Hunyadi defeated the armies of Ottoman Sultan Mehmet II forcing him to lift the Ottoman siege of Belgrade which had lasted since 4 July 1456.
Hunyadi forces consisted not only his own personal soldiers but also a large gathering of peasants who had flocked to Hunyadi’s banner after St. John of Capistrano had preached a crusade.
On 14 July 1456, Hunyadi arrived at Belgrade and managed to break the naval blockade the Ottomans had imposed on the city.
After managing to push back a major Ottoman attack, the peasants which had followed the banner of St. John of Capistrano spontaneously began a counter-attack on Mehmet’s army. St. John, finding himself surrounded by 2,000 crusaders eager to attack the Turks, led them toward the Ottomans while shouting, “The Lord who made the beginning will take care of the finish!” The Ottoman forces surprised by the crusader assault will break the siege and flee back to Constantinople.
During the siege, Pope Callixtus III had ordered that every Christian Church ring its bells every day at noon as a call for Christians to pray for the defenders of Belgrade. Since Christians in many countries in Western Europe did not hear of this command until after they received news that the Christian forces had been victorious, the ringing of the bells became understood as a sign of Christian victory. Pope Callixtus did not rescind his command and so the tradition of ringing the noon day bell in Catholic church began – a tradition which continues today.