Pope Celestine I

Celestine became bishop of Rome in September 422, at roughly sixty-three, and inherited a church splintering over doctrine. When Cyril of Alexandria appealed to him over Nestorius's controversial teachings, Celestine handed Cyril the authority to condemn Nestorius himself if he refused to recant - a move that set the stage for the Council of Ephesus in 431. In 429 he backed the Gallic bishops who sent Germanus of Auxerre to Britain to counter the spread of Pelagianism. Later he commissioned Palladius as bishop to the Scots of Ireland and northern Britain, extending Rome's pastoral reach into regions that had seen little formal church structure. He died in July 432, ten years into the job, having spent most of it deciding which teachings lived and which didn't.