Youngest son of a noble Italian family, he is the nephew of Pope Pi IV.
He established himself in the worldly and brilliant life of Rome, through his rigor and his work. He collaborated effectively in the resumption of the Council of Trent, interrupted for eight years.
Having become archbishop of Milan, he created seminaries for the training of priests. He cares for the poor while he himself lives poorly. He himself treated the plague victims when the plague ravaged Milan in 1576. He was canonized in 1610 by Pope Paul V