[2] He was made cardinal-priest of Santa Susanna by Pope Adrian I, and seemingly also vestiarius, or chief of the pontifical treasury, or wardrobe.

With the letter informing the Frankish ruler Charlemagne that he had been unanimously elected Pope, Leo sent him the keys of the confession of St. Peter, and the standard of the city, and requested an envoy.

On the occasion of the procession of the Greater Litanies, 25 April 799, when the pope was making his way towards the Flaminian Gate, he was suddenly attacked by armed men.

He was dashed to the ground, and an effort was made to root out his tongue and tear out his eyes which left him injured and unconscious.

[5] Duke Winiges of Spoleto sheltered the fugitive pope, who went later to Paderborn, where Charlemagne's camp then was[7] and where he was received by the Frankish king with the greatest honour.

In 754 Pope Stephen II had conferred on Charlemagne's father the dignity of Patricius Romanus, which implied primarily the protection of the Roman Church in all its rights and privileges; above all in its temporal authority which it had gradually acquired (notably in the former Byzantine Duchy of Rome and the Exarchate of Ravenna) by just titles in the course of the two preceding centuries.

[8] There is, however, no reason to doubt that for some time previous the elevation of Charlemagne had been discussed, both at home and at Rome, especially since the imperial throne in Constantinople was controversially occupied by a woman, Irene of Athens, and since the Carolingian dynasty had firmly established its power and prestige.

[7] The coronation offended Constantinople, which had seen itself still as the rightful defender of Rome, but Empress Irene, like many of her predecessors since Justinian I, was too weak to offer protection to the city or its much reduced citizenry.

[11] Leo helped restore King Eardwulf of Northumbria and settled various matters of dispute between the archbishops of York and Canterbury.

"[13] The Liber Pontificalis states Leo III put those shields at the top of St. Peter's entrance "in his love for and as a safeguard for the orthodox and catholic apostolic faith".