When was Pope Celestine II pope?

Celestine II reigned as the 165th pope from 26 September 1143–8 March 1144, during the high Middle Ages.

What number pope was Celestine II?

Celestine II was pope 165º — the 165th successor of St. Peter in the Catholic Church's official list of 267 popes.

What is Celestine II remembered for?

Celestine II served the Church during the high Middle Ages (26 September 1143–8 March 1144). Subject and later the sovereign of the Papal States.

Who came before and after Pope Celestine II?

Celestine II (165º) succeeded Pope Innocent II (164º) and was followed by Pope Lucius II (166º) in the line of apostolic succession.

Pope Celestine II (165º): Biography, Pontificate & Legacy

Celestine II was the 165th pope of the Catholic Church, reigning 26 September 1143–8 March 1144 during the high Middle Ages. Subject and later the sovereign of the Papal States.

Who Was Pope Celestine II?

This biography of Celestine II (165º) covers background, major events, and legacy in the line of St. Peter. During the high Middle Ages, the Bishop of Rome exercised teaching, sanctifying, and governing authority for the universal Church.

Early Life & Background

Before election he was known as Guido Guelfuccio di Castello. Born circa 1085 Città di Castello, Papal States, he entered a world shaped by politics and piety very different from today's global Church.

Historical Context

Celestine II led the Church in the high Middle Ages — an era of crusades, monastic reform, cathedral building, and intense negotiation between popes and emperors over who held ultimate authority in Christendom.

Pontificate & Key Events

The pontificate (26 September 1143–8 March 1144) centered on governance during the high Middle Ages.

Papal Acts & Achievements

Celestine II left a distinct mark through decisions that historians still debate and Catholics still study. His reign contributed to the continuous apostolic succession now numbering 267 popes.

Key Highlights

165th pope of the Catholic Church
Pontificate: 26 September 1143–8 March 1144
Shepherded the Church during the high Middle Ages
Successor of St. Peter in the official Catholic list

Legacy in the Catholic Church

Celestine II remains pope 165º in the Annuario Pontificio. Read against the high Middle Ages, his pontificate shows how Providence works through imperfect ministers without abandoning the Barque of Peter.

Why Catholics Study This Pope Today

Studying Celestine II helps Catholics see how the Holy Spirit guided the Church through the high Middle Ages — with human weakness and grace intertwined. Place this pope in context using our chronological list of all 267 popes and the biographies of his immediate predecessor and successor linked below.

Place in the Line of Succession

Celestine II followed Pope Innocent II (164º) in the unbroken line of apostolic succession from St. Peter. Upon his death or resignation, he was succeeded by Pope Lucius II (166º), who continued the mission of shepherding the universal Church. Explore the full chronological chain in our complete list of all 267 popes, or read the biographies of neighboring pontiffs linked below.