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.
Is the French version where he abuses a chambermaid at an inn?
Also: the French Knights were assembled in Provencal. “Graal” was a word unique to that region, meaning, “dish.” That the Sancta Caliz was a dish, not stemware, would have been quite surprising to the British. (It has since been made into stemware by the addition of a jeweled stem and base.)
Arthur I of Brittany disappeared, mysteriously. His supposed grave is on Avalon.
As punishment for John’s usurpment of the British throne, the Catholic Church placed an interdict on England. Restoring Arthur to the throne would mean that the English could once again receive from the chalice, which, according to Catholic doctrine would bestow eternal life on those who did so worthily.
Boudicca has all the necessary elements, in feminine gender. Oh, and she has the honorific of "BO" preceding it all. So, it's like Mr.Miss.Mrs King/Queen Arthur/Artorius.
Which may not answer all your questions but it does explain why Arthur wasn't sleeping with Guinnevere.
The Galician documents (in Spain) look back to an even earlier period (700 BC) and avoid all the adventures of the same ruling dynasty in Britain and Brittany.