When you talk of 5th century Scotland you have to be careful not to bring in the Scottii. They were still in Ireland and beginning to settle on the west coast of Scotland. However, at the same time, Cunedag from Manau Guotodin (Manau of Goddodin - British kingdom on the Forth) went south with his Votadini to reconquer Wales from other Irish invaders. The point that I'm keen to make is that people moved around Britain and took their legends and folk heroes with them. Arthur probably fought over a very wide area. Many of his battles were probably against other post-Roman British warlords in the north and in the west, but his fight against the incoming English must have been in the areas they were coming into. That means places like Catterick, Lincolnshire and the east coast in general. I remain convinced that the real resistance hero was Ambrosius. Gildas is the only near contemporary writer and he says nothing of Arthur. He does talk of Ambrosius and the decadence that came after him and he does imply that he was the victor of Badon.
Ambrosius gave his name to Amesbury and to many other places in the south east (Essex/Herts) - all hillforts or defensive settlements. That was where the real resistance to the Saxons was. After their final defeat, many British settlements remained in the south-east, even around London (look for place names with a Wal element or a ***** element) Others went westwards and took their embroidered stories of a great resistance leader with them. Somehow Ambrosius Aurelanius became shortened to a nickname - Arthur "the Bear".
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