Papacy
Paschal does not seem to have been quite pleased with Guy's zeal in his attacks upon Henry V. During the violent confrontations between Henry V and Paschal II's successor, Pope Gelasius II, the pope was forced to flee from Rome, first to Gaeta, where he was crowned, then to the Cluny Abbey, where he died on 29 January 1119. Guy was elected at Cluny on 2 February 1119. Nine cardinals took part in the election. Most of the other cardinals were in Rome. He was crowned at Vienne on 9 February 1119 as Calixtus II. In July 1119, Calixtus convened a synod at Toulouse addressing heresy, ecclesiastical discipline, and disputes within the French church. The council decreed that those who denied the Eucharist, infant baptism, ordination of priests, and lawful marriage were heretics.
At the outset, it appeared that the new pope was willing to negotiate with Henry V, who received the papal embassy at Strasbourg, and withdrew his support from the antipope he had proclaimed at Rome. It was agreed that pope and emperor should meet at the Château de Mousson, near Reims, and in October the new Pope opened the council at Reims attended by Louis VI of France with most of the barons of France and more than four hundred bishops and abbots. Henry V arrived for his personal conference at Mousson — not alone, as had been anticipated, but with an army of over thirty thousand men. Calixtus II, fearing that force was likely to be used to extract prejudicial concessions, remained at Reims. There, Calixtus II busied himself ineffectively with attempting a reconciliation between the brothers Henry I of England and Robert II of Normandy, and the council dealt with disciplinary regulations and decrees against lay investiture, simony, and clerical concubines. Since there was no compromise coming from Henry V, it was determined on 30 October 1119 that the Emperor and his antipope should be solemnly excommunicated.
Returning to Italy, where antipope Gregory VIII was supported in Rome by imperial forces and Italian allies of the emperor, Calixtus II managed to gain the upper hand amid clear demonstrations of popular support. The Imperial candidate was obliged to flee to the fortress of Sutri, where he was taken prisoner through the intervention of Norman support from the Kingdom of Sicily. He was transferred from prison to prison first near Salerno, and afterwards at the fortress of Fumo. The imperial allies in Rome soon disbanded.
