An Ardri, a Three-Fossed Fort and Arthur and Cadwy

I've recently been thinking of the Dindraethou I've recently identified pretty positively with Dawes Castle near Watchet.  Arthur is placed here with Cato/Cadwy, a known ruler of Dumnonia.  The presence of this last ruler had me thinking that Dindraethou had to be one of the Cadbury forts.  But I have no doubt that Dawes Castle is the right place - at least according to the Life of St. Carannog.

Suppose, however, that Dawes Castle (which is a Saxon fort and had nothing to do with Arthur) is a substitute for a Cadbury - a Cadbury that was called Dun Tradui/Tredui or the 'Triple-fossed fort" in the Irish CORMAC'S GLOSSARY?  And supposed this triple-fossed fort was Cadbury Castle at South Cadbury, with its evidence of major early medieval reuse?

Many years ago I naively suggested that the name Arthur could be from the Irish title ardri, 'high king.'  In CORMAC'S GLOSSARY, the high king Crimthann mac Fidaig is said to have founded Dun Tradui in Britain 'in the land of the Cornish Britains.'

Now, scholars will allow the Roman Artorius as being a decknamen used to replace an Artri or Arthr(h)i name, i.e. an Irish or British 'Bear-king.'  Could the same have happened with an Irish Ardri - perhaps originally applied as a title, not a proper name?

The Irish ard, 'high', became in Welsh ardd.  The /dd/ here is voiced like /th/. Thus is we allow a phonological development, Arddri, pronounced Arthri, could have been replaced by Artorius/Arthur.
At least this seems so to me.  I am, of course, checking with some Welsh linguists to see if such a development was at all possible.  It may not have been. I do find place-name components constantly alternating between ardd and arth.

For now - and purely for fun - let's run with the idea.  What would it mean to say that Arthur 'the Ardri' or High King was at Cadbury Castle?

Well, if I'm right and Arthur was the son of Illtud of the Ui Liathain, then he was acting in a similar capacity as his father, who served Pawl Penychen as master of soldiers.  In other words, Arthur was the general of the troops headquartered at Cadbury Castle. Perhaps he was given his "name" in memory of Crimthann mac Fidaig - as both men were Irish, and of Munster, and both occupied the same fort.  We are reminded that in the Geraint elegy, Arthur's men are said to be fighting at Llongborth. In the past I've tried to explain this away as being figurative/metaphorical.  He is called "ameraudur" or emperor (L. imperator).

Subsequent Arthurs would then all, in a sense, be "High-kings" - a glorified name if ever there was one!

Once again, though, I emphasize that this might be a very silly notion.  As soon as I know one way or the other, I will add an addendum to this post.

NOTE: As I suspected, this idea does not work.  Not a single Celtic or Welsh scholar I contacted thought it worth considering.  Their unanimous view is best summed up by the words of Dr. Simon Rodway from The University of Wales:

"In a word, 'no'. There is no evidence whatsoever for Middle Welsh *arddri, ardd only exists vestigially in place-names, have been usurped at an early stage by uchel, and if Irish ardri had been borrowed into Welsh, it would have sounded completely different to Welsh ears than Arthur. The sounds written in Modern Welsh as dd and th are totally different. Your arth for ardd can only be due to experimental early orthography."