of Genoese extraction, though born at Rome, was previously named John Baptist Castagna. He was archbishop of Rossano, member of the Council of Trent, repeatedly a legate to Germany and Spain, and, finally, a cardinal. He was elected to the papacy as the successor of Sixtus V, but died twelve days after the election, and before his consecration, Sept. 27, 1590. See Ranke, Die rom. Papste, etc. (Berl. 1836), 2, 219 sq.; Herzog, Real- Encyklop. s.v.