It has even been suggested that Arthur was a Weegie (Glaswegian)!
http://www.thenational.scot/news/aca...sgow-roots.826
Their are various suggestions (?fanciful) that the many hills in the Highlands that nowadays have "Arthur" as a component may be attributed to "ard-tir ..." or "ard-na..." so maybe Arthur's Seat is some such.
Alan