Heir to a marquisate he ceded to his brother in order to join the Jesuits, he died at twenty-three nursing plague victims.
Eldest son of the Marquis of Castiglione, born in 1568, he was destined for arms and the court: a page in Spain to the infante, he knew the intrigues of the Italian principalities before he was twenty. His decision to enter the Society of Jesus cost him three years of struggle with his father, which he finally won by renouncing his title in his brother's favour. A novice in Rome from 1585, he studied theology under Robert Bellarmine. In 1591 plague struck the city; the Jesuits opened a hospital and he gave himself to carrying and nursing the sick. He caught the disease and died on 21 June, aged twenty-three. Canonised in 1726, he was declared patron of Christian youth three years later. His feast falls on 21 June.
Shown young, in black cassock and white surplice, a lily in hand and a crucifix against his breast, sometimes a crown laid at his feet.