Written by Guide Catholic
Pope Pius IV (224º): Council of Trent — Complete Guide
Pontificate: 26 December 1559–9 December 1565 · Origin: Milão, Ducado de Milão · Birth name: Pius Quartus
Pius IV was the 224th pope of the Catholic Church, reigning 26 December 1559–9 December 1565 during the Renaissance papacy. Instituted the Tridentine Creed.
Who Was Pope Pius IV?
Pope Pius IV — 224º in the Catholic list — reigned 26 December 1559–9 December 1565 during the Renaissance papacy. Search interest often clusters around Council of Trent. Subject of the Duchy of Milan. This Guide Catholic profile gathers background, major acts, and legacy so you can read Pius IV beside neighboring pontiffs.
Early Life & Background
Before election he was known as Giovanni Angelo Medici. Born 31 March 1499 Milan, Duchy of Milan, he entered a world shaped by politics and piety very different from today's global Church.
Historical Context
Pius IV (#undefined) sat on Peter's chair amid artistic patronage, political intrigue, Reformation shocks, and the widening world of the Americas. Reopened and closed the Council of Trent(1563).
Pontificate & Key Events
The pontificate (26 December 1559–9 December 1565) centered on governance during the Renaissance papacy. Ordered public construction to improve the water supply of Rome.
Papal Acts & Achievements
Acts associated with Pius IV (#224, 26 December 1559–9 December 1565) still draw historians and Catholics who want more than a one-line summary. His reign remains a link in the succession now counted at 267 popes.
Key Highlights
- 224th pope of the Catholic Church
- Pontificate: 26 December 1559–9 December 1565
- Reopened and closed the Council of Trent(1563).
- Shepherded the Church during the Renaissance papacy
- Successor of St. Peter in the official Catholic list
Legacy in the Catholic Church
Pius IV remains pope 224º in the Annuario Pontificio. Set against the Renaissance papacy, Pius IV's choices show both the limits of any one pontiff and the continuity of the office he held.
Why Catholics Study This Pope Today
If you only remember one modern question about Pius IV, ask how his decisions served unity and truth under the pressures of the Renaissance papacy. Start with the concrete record: Instituted the Tridentine Creed. Reopened and closed the Council of Trent(1563). Where bulls, conciliar acts, or encyclicals survive from this reign, they repay readers who want primary sources rather than summaries alone. Then step back to the full list of 267 popes to see where Pius IV sits between crisis and consolidation.
Place in the Line of Succession
Pius IV followed Pope Paul IV (223º, 23 May 1555–18 August 1559) after a transition shaped by the politics and piety of their shared century. He was followed by Pope St. Pius V (225º, 7 January 1566–1 May 1572), whose biography continues the chain on Guide Catholic. For the full chronological map, see our complete list of all 267 popes — then read neighboring biographies for contrast, not only continuity.