A native of Capistrano, St. John became a Franciscan and was one of the great organizers of the struggle against the Mohammedans in the 15^th century, when they threatened to overrun the whole of Europe. Mohammed II had taken Constantinople and was already marching against Belgrade, when Pope Callixtus III called St. John Capistran to preach the crusade; assisted by the Hungarian John Hunyadi, he gathered a strong Christian army, which defeated the Turks in the great battle of Belgrade (1453). He died in 1456.