[muawiyah]

Merlin (Myrrdhn) was beyond cool. He went to Brittany some time after the onset of the Dark Age (15 years later the climate improved) and replanted the grapes there ~ which included running up what is now the Norman Coast beyond Mt. McWall.

He and others crossed France and went to the headwaters of the Rhone Valley and replanted the grapes there as well.

It's pretty easy to accept that he was a real person since, in fact, the grapes got replanted and due to some serious depopulation in the region it was easy enough for folks from Britain to get around (presumably on horses).

France has a "King Arthur" tradition in the West and in the Center as a consequence.

As far as the other characters are concerned, I think they are composites.

[dangus]

Yes, but the Continental Britons (France) also had an “Arthur, King of the Britons,” at the time when the Islandic Britons (England) had crowned the illegitimate John I. Arthur I, Duke of Brittany was the legal heir of Richard the Lion-hearted. And during his reign, the French Knights gathered at a Round Table to liberate the Sancta Caliz (Holy Grail) from the Black Knights (Moors) of Valencia, Spain (Hibernia).

Can’t help but suppose that had something to do with the French legends of King Arthur.

[ElkGroveDan]

it was easy enough for folks from Britain to get around (presumably on horses).

Nah... they were banging coconuts together.