This month, February 2017, I visited the area I had identified four years ago as where King Arthur fought his second to fifth battles. In my post “King Arthur of Somerset: early battles above the River Divelish”, I explained that the Historia Brittonum “says Arthur’s four battles on the borders of Lindinis were ‘above the river which is called Dubglas’,” and that “linguists inform us that the name Divelish can have derived from Dubglas. The River Divelish rises on the N Dorset Downs south of Ibberton.”
The location is far more spectacularly credible than I had imagined as the site of Arthur’s early skirmishes to prove his worthiness to rule the Kingdom of Lindinis by defending its southern border.
In what is now deeply rural north Dorset, two miles south of Ibberton, the rim of Bulbarrow Hill gives large vistas to southward over the valleys below. Any general who had command of south Somerset but needed to guard against enemies from his south would want to control and defend Bulbarrow Hill. Correspondingly, Bulbarrow defended would be extremely difficult to conquer from the south with anything less than overwhelming force.
Today there is a sign informing us that this scenic location is on the “Wessex Ridgeway” long-distance footpath. The footpath is a recent creation; but the ridge, one can truthfully say, is as old as the hills, and the sign tells us that it was “used by traders and invaders”.
There is even an Iron Age fort on the ridge, called Rawlsbury Camp (a mile west of the sign), about 500 metres from one of the sources of the River Divelish. King Arthur’s base for his second to fifth battles? The pieces of the jigsaw fit together: credible purpose, credible strategically, credible linguistically. One can’t prove it, of course, but it would certainly make sense.
 Equally so, incidentally, if the anciently Dubglas-named river be the stream flowing from Higher Ansty (below Rawlsbury) southwards through Dewlish, as others have suggested.