Pope Pius IV, born Giovanni Angelo Medici, was Pope from 25 December 1559 to his death in 1565. He is known for presiding over the final session of the Council of Trent.
On the death of Pope Paul IV, he was elected pope on 25 December 1559, taking the name Pius IV., and installed on 6 January 1560. His first public acts of importance were to grant a general pardon to the participants in the riot after the death of his predecessor, and to bring to trial the nephews of his predecessor. One, Cardinal Carlo Carafa, was strangled, and Duke Giovanni Carafa of Paliano, with his nearest associates, was beheaded.
Pius IV died on 9 December 1565. He was buried in Santa Maria degli Angeli. His successor was Pius V.