A historical Arthur need have done none of these things. By the time we hear of twelve battles against the Saxons and of Medraut, we are already about three and a half centuries on from when the putative real Arthur would have lived. That's the same distance in time between us and the Glorious Revolution of 1688. That's plenty of time for stories to evolve and grow. Two or three short references to Dick Turpin as he exists in the minds of people living in the 21st century would probably have very little bearing on the real man and his deeds. We'd see him as a noble highwayman who completed a mammoth ride to York. Which he wasn't and which he didn't.A historical King Arthur would have to have been the commander in the 12 Battles of Arthur against the Saxons in the HIstoria Brittonum, sometime between 450 and 550. A historical Arthur would have to have fought a Battle of Baden about 516/17/18 and been killed along with an ally or enemy name Medraut at the Battle of Camlann about 537/38/39 according to the Annales Cambriae. And there is only a little bit more than might be added from other very early sources to make a historical King Arthur.