"Charlemagne, claimed by the Church as a saint, by the French as their greatest king, by the Germans as their compatriot, by the Italians as their emperor, heads all modern histories in one way or another; he is the creator of a new order of things," wrote the historian Sismondi in 1821. In this fascinating book, available for the first time in an English translation, Robert Morrissey explores a millennium's worth of history and myth surrounding Charlemagne...