Is it really necessary to present Charlemagne? He is one of the few known characters of the Middle Ages. If the Emperor is so familiar to us, it is because his heritage has been claimed since the Carolingian dynasty, up to the construction of the European Union, passing through the kings of France, the Holy Empire, or even Napoleon. But beyond the legendary figure mobilized and remodeled through the ages according to political needs, what about the historical figure? Bruno Dumézil retraces in this course the story of Charles I, who was never named Charlemagne during his lifetime, the story of a king who took on imperial dignity and wrested Christian authority from Constantinople. An Emperor who reunited the fragmented Christian West since the fall of the Western Roman Empire.