Pope Leo III

Prompted by jealousy or ambition, or the thought that only someone of the nobility should hold the office of pope, a number of relatives of Adrian I formed a plot to render Leo unfit to hold his office. 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. He was rescued by two of Charlemagne's missi dominici, who came with a considerable force.[2] Duke Winiges of Spoleto sheltered the fugitive pope, who went later to Paderborn, where Charlemagne's camp then was.[4] He was received by the Frankish king with the greatest honour at Paderborn.[2] This meeting forms the basis of the epic poem Karolus Magnus et Leo Papa.

Leo was accused by his enemies of adultery and perjury. Charlemagne ordered them to Paderborn, but no decision could be made. He then had Leo escorted back to Rome. In November 800, Charlemagne himself went to Rome, and on 1 December held a council there with representatives of both sides. Leo, on 23 December, took an oath of purgation concerning the charges brought against him, and his opponents were exiled.[2]

Charlemagne's father, Pepin the Short, defended the papacy against the Lombards and issued the Donation of Pepin, which granted the land around Rome to the pope as a fief. In 754 Pope Stephen II had conferred on Charles'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.[4]

Two days after his oath, on Christmas Day 800, Leo crowned Charlemagne as emperor. According to Charlemagne's biographer, Einhard, Charles had no suspicion of what was about to happen, and if informed would not have accepted the imperial crown.[5] 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.[4] 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.

In 808, Leo committed Corsica to Charlemagne for safe-keeping because of Muslim raids, originating from Al-Andalus,[6] on the island.[7] Nonetheless, Corsica, along with Sardinia, would still go on to be occupied by Muslim forces in 809 and 810.[8]

Leo helped restore King Eardwulf of Northumbria and settled various matters of dispute between the archbishops of York and Canterbury.[2] He also reversed Adrian I's decision in regards to the granting of the pallium to Bishop Hygeberht of Lichfield. He believed that the English episcopate had been misrepresented before Adrian and that therefore his act was invalid. In 803, Lichfield was a regular diocese again.[9]

When asked to confirm the decision of the 809 Council of Aachen, Leo, though affirming the orthodoxy of the term Filioque and approving of its use in catechesis and personal professions of the faith, explicitly disapproved the addition of the filioque to the Creed of 381.[10][11] Around this time, he ordered two heavy silver shields, containing the original text of the Creed in both Greek and Latin, to be made and placed in St. Peter's Basilica,[10][11] adding: "Haec Leo posui amore et cautela orthodoxae fidei" ("I, Leo, put these here for love and protection of orthodox faith").