By Anne Leader
On 29 November 800, Charlemagne arrived in Rome with a mission to investigate corruption charges against Pope Leo III (r. 795-816). A council was convened on 1 December with those for and against the pope, who had been accused of adultery and perjury. Though the gathered bishops made clear that they had no authority to judge the pope, Leo sought to remove all suspicion by swearing his innocence. Twenty-three days later, Leo swore an oath of spiritual cleansing, or purgation, while his enemies were sent into exile – a less brutal punishment than the death sentences which had been passed prior to Leo’s intervention. On Christmas Day, Leo crowned Charlemagne as Holy Roman Emperor in St. Peter’s Church, an act that offended the Byzantine crown in Constantinople, at that time held by Empress Irene of Athens (c. 752-803)
Pope Leo III, Lateran Palace mosaic, detail and full view, ca. 799 CE, Rome
Raphael, Coronation of Charlemagne, detail and full view; Oath of Leo III, fresco, 1514-15, Stanza dell’Incendio, Vatican Palace, Rome