440–461

Leo the Great: pontificate, the doctrine of Roman primacy, and the meeting with Attila

Leo I, bishop of Rome from 440 to 461, became famous for elevating the papacy. He taught that the apostle Peter had passed his supreme authority to the bishops of Rome, so that in the person of the pope Peter himself addresses the Church. Papal authority thus rests on this succession rather than on the political status of the capital.

When Hilary of Arles arbitrarily deposed and appointed bishops in Gaul, Emperor Valentinian III, at Leo's urging, issued a decree. It forbade bishops from making major decisions without Rome's consent.

In 452 Leo personally went out to meet the Huns of Attila and persuaded them not to march on Rome. In 455 he negotiated with the Vandal Genseric. Though unable to prevent the sack of the city, he saved it from burning and many killings.

Leo was the first to be called pope in the modern sense. His theological legacy also includes the "Tome," a Christological letter that played a key role in the disputes over the natures of Christ.