Pope Pius IV is known for completing the work of the Council of Trent, which brought about key reforms in Catholic doctrine and practice. He also worked to stabilize the Church in the aftermath of the Reformation. Birth name: Giovanni Angelo Medici Nationality: Papal States Born: April 9, 1499 Died: December 19, 1565 Pontificate: January 14, 1560 – December 9, 1565