Pope Cornelius was the bishop of Rome from 6 or 13 March 251 to his martyrdom in June 253. He was pope during and following a period of persecution of the church and a schism occurred over how repentant church members who had practiced pagan sacrifices to protect themselves could be readmitted to the church. Cornelius agreed with Cyprian of Carthage that those who had lapsed could be restored to communion after varying forms of penance. That position was in contrast to the Novatianists, who held that those who failed to maintain their confession of faith under persecution would not be received again into communion with the church. That resulted in a schism in the Church of Rome that spread as each side sought to gather support. Cornelius held a synod that confirmed his election and excommunicated Novatian, but the controversy regarding lapsed members continued for years.
The persecutions resumed in 251 under Emperor Trebonianus Gallus. Cornelius was sent into exile and may have died from the rigours of his banishment, but later accounts say that he was beheaded.