Last I heard, Arthur was fictional""
Alot of people believe he was real.
I tend to sway toward real. Too much reference in stories, etc, to not have been. Too many actual historical places referenced...
Well theyre teaching in public school british lit classes he was real, so it MUST be true. /sarc
Owain Ddantgwyn - Seems a good candidate
And if he can be connected to Wroxeter (then known as Caer Guricon) which was extensively rebuilt c.500 - we have Camelot