The legendary image of Arthur, the once and future king, who will return in England’s direst need to deliver her from her enemies, is somewhat undercut by the fact that, if he existed at all, Arthur actually fought against the English as a champion of the native Britons, the people who would become the Welsh. But Arthur’s very existence is a moot point.
The earliest definite reference to him is in the Historia Brittonum (History of the Britons), which was written in Wales around 830, so at least three centuries later. In the Historia, Arthur is the dux bellorum (duke of battles) rather than a king, who leads the Britons to 12 victories over the Anglo-Saxons, the last of which at Mount Badon. This is interesting because Gildas also talks about a victory for the Britons at Mount Badon, the battle taking place in the year of his birth, as well as naming the man who rallied the Britons after the shock of the initial Saxon invasion. Unfortunately, for Arthurian apologists, Gildas names this war leader as Ambrosius Aurelianus, rather than Arthur. That the Britons had war leaders who rallied them against the invaders seems certain: whether the greatest of these was really called Arthur, we simply cannot say.