Which pope crowned Charlemagne emperor in Rome?

Pope Leo III crowned Charlemagne emperor in Rome. The ceremony took place at St. Peter’s Basilica on Christmas Day in 800, when Leo proclaimed Charlemagne “emperor of the Romans” and placed the imperial crown on his head.

The coronation followed a period of political danger for Leo. Supporters of his predecessor, Pope Adrian I, had challenged him, and Charlemagne provided protection. Their alliance helped Leo return to Rome and strengthened Charlemagne’s authority in Italy.

The event revived an imperial title in western Europe more than three centuries after the deposition of the last western Roman emperor, Romulus Augustulus, in 476. It also created tension with the Byzantine Empire in Constantinople, which considered itself the continuation of the Roman Empire.

A common mix-up is confusing Leo III with Pope Stephen II, who crowned Charlemagne’s father, Pepin the Short, king of the Franks in 754. Leo III was the pope associated with Charlemagne’s imperial coronation.