 On 11 May 1587 he opted for the order of cardinal bishops, taking the suburbicarian see of Palestrina.He was named papal legate to the Campagne and Maritime Province on 13 May 1587.He was a participant in the 1st papal conclave of 1590 that elected Pope Urban VII; the 2nd papal conclave of 1590 that elected Pope Gregory XIV; the papal conclave of 1591 that elected Pope Innocent IX; and the papal conclave of 1592 that elected Pope Clement VIII.