one of the greatest Franciscan preachers of the 15th century and leader of an army that liberated Belgrade from a Turkish invasion. San Juan Capistrano, the mission in California made famous by the swallows that return there each year, was named for John.

In 1412 John became magistrate of Perugia, Papal States, where a civil quarrel caused his imprisonment. He experienced an emotional conversion while in prison and after his release in 1416 became a Franciscan. He was ordained in 1426, after which his fame as a preacher spread because of his efforts to restore doctrinal harmony and promote education. He became the principal force in the founding of the Franciscan Observants, a severely ascetic group of friars who separated from the more liberal Conventuals. In 1451 he was sent to Austria by Pope Nicholas V to convert the Hussites (followers of the Bohemian religious reformer Jan Hus). Aware of the Turkish threat to eastern Europe, he helped raise and lead the army that lifted the Turkish siege of Belgrade in 1456. He died of plague upon returning from his crusade.