Pope Fabian
After the martyrdom of Pope Fabian during the Decian persecution, a Roman priest, Novatian, opposed the election of Pope Cornelius in 251, on the grounds that Cornelius was too liberal in accepting lapsed Christians. Novatian held that lapsed Christians, who had not maintained their confession of faith under persecution, may not be received again into communion with the church. He was consecrated bishop by three bishops of Italy and declared himself to be the true Pope. He and his followers were excommunicated by a synod held at Rome in October of the same year. Novatian is said to have suffered martyrdom under the Emperor Valerian I (253–60).