Presses Universitaires de France and Fremeaux & Associates offer this biography of King Arthur, told and explained by Alban Gautier, professor of medieval history at the University of Caen. Did King Arthur really exist? Arthur is a character, at the same time historical, literary, and mythical. From Britain in the fifth century, during the decline of the Roman Empire, until today, Arthur has continued to exist under many faces. His heroic figure has been used for diametrically opposing political purposes, among these the Welsh people during the ninth century, the Plantagenets, and the Kings of the Tudor dynasty. To explore the character in his time, one must put him back into his era. It is this historical enigma that Alban Gautier proposes here to explore.