Who was King Arthur? How did the story originate? Through careful research of the many primary documents, a picture of the true Arthur can in fact be set down. He reached power shortly after the Romans evacuated Britain at the end of the fifth century and died at the Battle of Camlann. He became king at 15 under the name of Ambrosius Aurelianus and fought against the Saxons on the mainland as Riothamus, thus explaining the regeneration motif so closely tied to the mythical Arthur. This study reveals that the integrity and ideals central to Arthurian myth were very much a part of the real Arthur.