The Siege of Belgrade (1456) or Battle of Belgrade or Siege of Nándorfehérvár occurred from July 4–22, 1456. After the fall of Constantinople in 1453, the Ottoman Sultan Mehmed II rallied his resources in order to subjugate the Kingdom of Hungary. His immediate objective was the border fort of the town of Belgrade (in old Hungarian Nándorfehérvár). John Hunyadi, the Voivode of Transylvania, who had fought many battles against the Turks in the previous two decades, prepared the defenses of the fortress. Since 22 July 2011, the date when Christian forces led by John Hunyadi and John of Capistrano defeated the Ottoman Turks besieging Belgrade in 1456, has been a national memorial day in Hungary.