In autumn of 800, Charlemagne paid a momentous visit to Rome, during which he was crowned emperor by Pope Leo. For centuries, scholars have debated the reasons for the imperial coronation of Charlemagne. Whose idea was the coronation, Charlemagne’s or Leo’s? Did Charlemagne plan the ceremony or did he merely accept the title of emperor? What did he have to gain from it? What were Pope Leo’s motives?

Though definitive answers will probably never be found, several things seem certain. First, after the coronation, Charlemagne considered himself an emperor ruling a Christian people. Through his motto, Renovatio romani imperi (Revival of the Roman Empire), Charlemagne was consciously perpetuating old Roman imperial notions while at the same time identifying with the new Rome of the Christian Church. Second, Leo’s ideas about gender and rule undoubtedly influenced his decision to crown Charlemagne. In 800, the ruler of the Byzantine Empire was the empress Irene, the first woman to rule Byzantium in her own name, but Leo did not regard her authority as legitimate because she was female. He thus claimed to be placing Charlemagne on a vacant throne. Third, both parties gained: the Carolingian family received official recognition from the leading spiritual power in Europe, and the papacy gained a military protector.

The coronation of Charlemagne, whether planned by the Carolingian court or by the papacy, was to have a profound effect on the course of German history and on the later history of Europe. In the centuries that followed, German rulers were eager to gain the imperial title and to associate themselves with the legends of Charlemagne and ancient Rome. Ecclesiastical authorities, on the other hand, continually cited the event as proof that the dignity of the imperial crown could be granted only by the pope.