Laura Ferro. The future Pope explains in detail the circumstances of the boy's conception, which took place in 1547, in Bologna after the Council of Trent had moved to that city; his motive was to assure his inheritance rights following the death (in 1546) of his father Cristoforo Boncompagni."

He also served as a legate to Philip II of Spain (1556-1598), being sent by the Pope to investigate the Archbishop of Toledo