The Cardinal's grandfather, named Leo after Pope Leo IX, who baptized him, was a faithful adherent of Gregory VII; Leo's son, Peter, from whom the family acquired the appellation of Pierleoni, became leader of the faction of the Roman nobility which was at enmity with the Frangipani.
After finishing his education at Paris, he became a monk in the monastery of Cluny, but before long he was summoned to Rome by Pope Paschal II and created Cardinal-Deacon of SS.
Moreover, of the commission of eight cardinals, to which, in apprehension of a schism, it was decided to leave the election, one of them being Pierleone, five were opposed to the ambitious aspirant.