Saint John of Capistrano, a fifteenth-century Franciscan friar and jurist, becomes a noted preacher, reformer, and defender of Catholic orthodoxy. He travels widely through Europe, promotes moral reform, and combats heresy. After the fall of Constantinople, he helps organise Christian resistance to the Ottoman advance and plays a significant role in the relief of Belgrade. He dies of plague in 1456, is canonized in 1690, and is recognised as patron saint of military chaplains.