The precedent of empire and the promise of return lay at the heart of King Arthur's appeal in the Middle Ages. Both ideas found fullness of expression in the twelfth century: monarchs and magnates sought to recreate an Arthurian golden age that was as wondrous as the biblical and classical worlds, but less remote. Arthurianism, the practice of invoking and emulating the legendary Arthur of post-Roman Britain, was thus an instance of medieval medievalism. This book provides a comprehensive history of the first 150 years of Arthurianism, from its beginnings under Henry II of England to a highpoint under Edward I. It contends that the Plantagenet kings of England mockingly ascribed a literal understanding of the myth of King Arthur's return to the Brittonic Celts whilst adopting for themselves a figurative and typological interpretation of the myth. A central figure in this work is Arthur of Brittany (1187-1203), who, for more than a generation, was the focus of Arthurian hopes and their disappointment.