[Irish_Thatcherite]

So, it's before the Angles, Saxons and Jutes? It must be mainly Celtic.

[Harmless Teddy Bear]

Yep. With a bit of Roman thrown in but mostly Celtic.

The Romans were leaving, the Saxons were making small incursions and the Celts were mostly leaderless.

We have a 6th century poem that makes reference to him, (maybe!) but rather indirectly.

He charged before three hundred of the finest,
He cut down both centre and wing,
He excelled in the forefront of the noblest host,
He gave gifts of horses from the herd in winter.
He fed black ravens on the rampart of a fortress
Though he was no Arthur.

Arthur was obviously an ideal to which warriors in Wales aspired.

My personal opinion is that it was Christianized about a century or so later. Then in the 10th century it was fit into the tradition of the contemporary Anglo-Saxons kings with crowns and fair maidens and castles.

Have I bored you yet?