St. John Capistran, who was born in 1385 (died 1546) distinguished himself in early life as a public man. At the age of thirty he entered the Franciscan Order and was ordained a priest. From that time his zeal for the salvation of souls was unceasing. In a crusade against the Turks during the Fifteenth Century he was the leading spirit. He was canonized in 1724, and Pope Leo XIII ordered that his feast should be observed by the whole Church. To his preaching and prayer is attributed the victory over the Turks under the walls of Belgrade. The prayers in the mass make allusion to this triumph and to the fervent devotion practiced by the great Franciscan toward the holy name of Jesus.
(Source: Fr. Lasance, The New Roman Missal)