The evidence for Arthur being a genuine historical figure is very similar to that for Urien. Both appear in the Welsh pedigree lists, Arthur in HG 2 and Urien in HG 8.
|Gen.||HG 2||HG 8|
That Urien became incorporated into the Arthurian cycle is not necessarily a creation of the High Medieval writers since Urien belonged to gen. 1. Taliesin was a contemporary of Arthur and Urien. It is, consequently, not suprising that he wrote praise poetry about both, in The Chair of the Sovereign and Urien of Yrechwydd respectively.
St. Kentigern, who died in 614 according to the AC, was incorrectly identified with Cyndeyrn Garthwys, a grandson of Urien. I believe Kentigern was Cyndeyrn Fendigaid of gen. 1. This assertion is given support by the V. Kentigerni 24 which describes how a king called Melconde Golganu attempted to stop Kentigern from constructing a monastery. The king is identified as Maelgwn Gwynedd who belonged to gen. 0 and so could well have interacted with Kentigern.
The year of Kentigern’s birth can be determined with reasonable certainty. He is said to have died in 612 or 603. The latter date is more likely as his death occurred on 13 January on a Sunday. He is said to have lived 185 years which is likely to be an error for 85 years, giving a birthdate of 518.
|Gen.||ABT 18a||ByS G 18
|1||Cyndeyrn Fendigaid||Urien Rheged|
This confusion can be seen in triad 1 which describes Cyndeyrn as Chief of Bishops in the North but gives him the wrong cognomen, i.e. Garthwys. The error may have resulted in further misidentifications as indicated in the above table below.
||ByS G 18|
|3||Cyndeyrn Fendigaid||Cyndeyrn Garthwys|
However, Cyngar (Hound love) and Cynfarch (Hound horse), the name of Urien’s father, are not the same.
I believe that doubt has been created concerning Arthur’s existence because of the supernatural stories built around him by later writers. This sort of phenomenon has similarly cast doubt, in the minds of some, on the historicity of Jesus.