Pietro was born in a powerful Roman family and, as second son, was destined to the church. He studied in Paris and entered the BenedictineAbbey of Cluny. Later he was to Rome and occupied several important positions. On 1130, Pope Honorius II was dying and Pietro was determined to succeed him, even if it meant huge bribery. Despite support of most noble families and the city's inhabitants, Pietro's political enemies could not condone with 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 popes in February 23, beginning the schism.
Both popes remained in Rome and Anacletus tried to win the population for his side by spending enormous amounts of his fortune in 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 were a duke William X of Aquitaine who decided for the antipope against the will of its own bishops and the influential support of King Roger of Sicily. Despite the fact, Innocent II was forced to leave the city and live in Pisa, while Anacletus II 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 finished 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 usary, clerical marriage, etc.
Stroll, Mary. The Jewish Pope: Ideology and Politics in the Papal Schism of 1130. New York: E.J. Brill, 1987. (http://www.worldcatlibraries.org/wcpa/ow/5d5a330fc7a5d8fca19afeb4da09e526.html)
The official acts of AnacletusII were declared null and void, the bishops and priests ordained by him were with few exceptions deposed, the heretical tenets of Pierre de Bruys were condemned.
In the East, Innocent II curbed the pretension to independence on the part of William, Patriarch of Jerusalem and of Raoul, Patriarch of Antioch (Hergenröther, II, 410).
Innocent II is praised by all, especially by St. Bernard, as a man of irreproachable character.
AnacletusII The title which was taken by Cardinal Pietro Pierleone at the contested papal election of the year 1130.
Though in a hopeless minority, they had the advantage that four of their number were cardinal bishops, to whom the legislation of Nicholas II had entrusted the leading part in the election.
The consecration was performed by the Bishop of Ostia, to whom that function specially belongs." Meanwhile Anacletus maintained his popularity in Rome by the lavish expenditure of his accumulated wealth and the plundered treasures of the churches.