Pierloni was born to a powerful Roman family and, as second son, was destined to the Church. He studied in Paris and entered the Benedictine Abbey of Cluny. Later he went to Rome and occupied several important positions. In 1130, Pope Honorius II was dying and Pierloni was determined to succeed him, even if it meant huge bribery. Despite support of most noble families and the city's inhabitants, Pierloni's political enemies could not condone his ambitions and forced Cardinal Gregory Papareschi to stand for election. He was elected as Pope Innocent II, but the Pierloni faction did not accept the result and proclaimed him as Anacletus II. Both men were consecrated as pope on February 23, beginning the schism.
Both popes remained in Rome and Anacletus tried to win the population to his side by spending enormous amounts of his fortune on gifts and exuberant parties. European governants, specially Lothar II, Holy Roman Emperor, supported Innocent II, leaving Anacletus with few patrons. The most important of these was a duke, William X of Aquitaine, who decided for the antipope against the will of his own bishops and the influential support of Roger II of Sicily, whose title of "King of Sicily" Anacletus had approved shortly after his accession. Due to Roger's powerful support of Anacletus, Innocent II was forced to leave Rome and live in Pisa, while Anacletus occupied Rome. Saint Bernard of Clairvaux was Innocent's most eloquent supporter and convinced all the supporters of Anacletus to join Innocent II's side after the death of Anacletus II. Nevertheless the schism only ended with Anacletus' death in 1138. After this, Innocent returned to Rome and ruled without opposition. Innocent II quickly convened the Second Lateran Council in 1139 and resolidified the Church's teachings against usury, clerical marriage, and other problems.