Charlemagne is crowned emperor

Pope Leo III crowned Charlemagne, king of the Franks, as emperor in Rome. The title linked a large European realm to the memory of ancient Rome.

Accounts differ on how much Charlemagne planned the ceremony.

Context

In April 799, Leo III was attacked during a procession in Rome. His assailants reportedly meant to blind him and cut out his tongue, which would have disqualified him from the papacy. He fled to Charlemagne at Paderborn, and a commission returned him safely to Rome that November.

Charlemagne travelled to Rome in autumn 800 to restore order to the church. On 23 December Leo publicly swore an oath of innocence of the charges against him. Two days later, at St Peter's Basilica, he crowned Charlemagne emperor, during a gathering held for the consecration of Charlemagne's son Louis as king.

By then Charlemagne had conquered the Lombards in northern Italy and Bavaria, defeated the Avars in what is now Austria and Hungary, and fought the Saxons for decades. He had also given money and land to the church and protected the popes, so the title recognised power he already held.

Britannica calls the coronation a revolutionary act and says Leo appears to have planned it in advance, which also strengthened his own position. It set the precedent that only the pope could confer the imperial crown. Byzantium, which had its own emperor, regarded Charlemagne as a usurper, and the rivalry deepened the East-West divide.