"Pope Leo III (Latin: Leo; fl. 12 June 816) was Pope and ruler of the Papal States from 26 December 795 to his death in 816. ...
Protected by Charlemagne from his enemies in Rome, he subsequently strengthened Charlemagne´s position by crowning him Holy Roman Emperor and "Augustus of the Romans".
Leo was assaulted in Rome by partisans of the late Pope Adrian I, and fled to Charlemagne at Paderborn. The King of the Franks arbitrated the dispute, restoring Leo to his office. Leo subsequently crowned Charlemagne as Roman Emperor, which was not approved in Constantinople, although the Byzantines, occupied with their own defenses, were in no position to offer much opposition." - (en.wikipedia.org 31.01.2020)
