During the Siege of Belgrade in 1456, Hungarian noblemen John Hunyadi (leader of the Hungarian royal army) and Mihály Szilágyi (Captain of the castle of Nándorfehérvár/ Belgrade) defended the city against the onslaught of the Ottoman Sultan Mehmed II. During the siege, Pope Callixtus III ordered the bells of every church to be rung every day at noon, as a call for believers to pray for the defenders of the city. However, in many places, news of the victory arrived before the order, and the ringing of the church bells at noon thus transformed into a commemoration of the victory. The Pope didn't withdraw the order, and Catholic churches still ring the noon bell to this day.