Having already previously seen the ancient Welsh poem Y Goddodin refer to a battle undertaken by a tribe based in Edinburgh, the earliest mention of Arthur; we can try and trace the provenance of other ancient Welsh poems that mention Arthur in a historical sense.
This may seem an impossible task, but W.F. Skene in Arthur and the Britons in Wales and Scotland makes a telling point: "It is very remarkable how few of these poems contain any mention of Arthur. If they occupied a place, as has sometimes been supposed, in Welsh literature, subsequent to the introduction of the Arthurian romance, we should expect these poems to be saturated with him and his knights, and his adventures; but this is not so. Out of a large body of poems in the Ancient Books, there are only five which mention him at all; and then it is the historical Arthur, the Guledig, to whom the defence of the wall was entrusted, and who fights the twelve battles in the north, and finally perishes at Camlan."
Skene seems confident that the Arthur of the ancient Welsh poetry belongs to Scotland. I plan to show that in the handful of poems that mention the historical Arthur, all of them can be firmly placed in Scotland.