Two schools of thought arose after the persecution. One side, led by Novatian, a priest in the diocese of Rome, believed that those who had stopped practising Christianity during the persecution could not be accepted back into the church, even if they repented. He held that idolatry was an unpardonable sin, and that the Church had no authority to forgive apostates, but that their forgiveness must be left to God; it could not be pronounced in this world. The opposing side, including Cornelius and Cyprian of Carthage, believed that the "lapsi" could be restored to communion through repentance, demonstrated by a period of penance.