Pope Celestine II (; died 8 March 1144), born Guido di Castello, was head of the Catholic Church and ruler of the Papal States from 26 September 1143 to his death in 1144. Early life Guido di Castello, possibly the son of a local noble, Niccolo di Castello, was born either in Città di Castello, situated in Paterna Santa Felicità upon the Apennines, or at Macerata in the March of Ancona. Guido had studied under Pierre Abélard, and eventually became a distinguished master in the schools. Eventually Guido began his career in Rome as a subdeacon and a scriptor apostolicus under Pope Callixtus II. He was created Cardinal-Deacon of Santa Maria in Via Lata by Pope Honorius II in 1127; as such, he signed the papal bulls issued between 3 April 1130 and 21 December 1133. In the double papal election of 1130 he joined the obedience of Pope Innocent II. In December 1133 Innocent promoted him to the rank of Cardinal-Priest of San Marco. He signed the papal bulls as S.R.E. indignus sacerdos between 11 January 1134 and 16 May 1143. As the cardinal of San Marco's, he supported Innocent's claims with regards to Monte Cassino, and as a mark of his confidence in him, Innocent made Guido the rector of Benevento. Afterwards, he made him a papal legate to France in 1140. He participated in the papal election of 1143, the first undisturbed papal election that Rome had seen for eighty-two years, and was elected pope two days after the death of Innocent II, on 25 September 1143, taking the name of Celestine. Papacy Celestine II governed the Catholic Church for only five months and thirteen days from his election until his death on 8 March 1144. Upon his accession he wrote to Peter the Venerable and the monks of Cluny, asking them to pray for him, while he was congratulated by Arnulf of Lisieux. Regardless of the brevity of his reign, he was prepared to chart a very different course from that of his predecessor. He was opposed to Innocent II's concessions to King Roger II of Sicily and refused to ratify the Treaty of Mignano ("a foolish policy, which he survived – just – long enough to regret"). He was in favor of the Plantagenets' claim to the English throne, and was therefore opposed to King Stephen of England. To emphasise this shift, he refused to