The web site, Early British Kingdoms, has an entire section devoted to King Arthur, particularly who he could have been if he wasn’t ‘Arthur’, as no leader of that name in the middle 6th century or earlier seems to fit that profile.
The possibilities are quite endless, especially if you consider Scots as well as Welsh rulers. For example, Norma Lorre Goodrich places Arthur at Carlisle (as Camelot) and as Arthur ic Uibar, in her book ‘King Arthur’. In the book “Arturius – A Quest for Camelot,” David Carroll suggests that King Arthur is, in fact, the historical late 6th century Prince Artuir, eldest son of King Aidan of Dalriada. Carroll believes that Artuir ruled Manau Gododdin, the narrow coastal region on the south side of the the Firth of Forth, during his father’s Dalriadan reign. He died at the Battle of the Miathi in 582. Carroll equates this with Camlann and places it in the same kingdom. “What is more natural than for this Prince to make his capital at the old Roman Fort of Colania (which Carroll refers to as Ad Vallum) in the centre of Manau Gododdin, a place called Camelot in the past and still called Camelon today?” http://www.earlybritishkingdoms.com/archaeology/camelon.html
In an earlier post, I postulated that Arthur could be a substitute for Gwydion, son of Don, one of the Welsh mythological heroes, as well as his links to Cadwaladr ap Cadwallon, especially given that ‘Cadwaladr’ means ‘battle-leader’, the title attributed to Arthur (Dux Bellorum) by Nennius, rather than ‘king’.
Other possibilities abound, however. This site, makes an argument in favor of a Prince Arthur in Scotland, who had a daughter named Gwenwynwyn. Another argues that Arthur was really Cuneglas (or Cynglas in Welsh) one of the five tyrants named in Gildas’ writings (one of the stumbling blocks to belief that Arthur existed is that Gildas does not mention him). Gildas writes:
“Why have you been rolling in the filth of your past wickedness,you bear, rider of many and driver of the chariot of the Bear’s Stronghold, despiser of God and oppressor of his lot, Cuneglasus, in Latin ‘red butcher’? Why do you wage such a war against men and God? – against men, that is our countrymen, with arms special to yourself, against God with infinite sins. Why, aside from countless other lapses, have you rejected your own wife and now, against the ban of the apostle, who says that adulterers cannot be citizens of the kingdom of heaven, do you cast your eyes, with all the reverence (or rather dullness) of your mind, on her villainous sister, although she has promised to God perpetually chaste widowhood, like, as the poet says, the supreme tenderness of the dwellers in heaven? Why do you provoke with continual injuries the groans and sighs of the holy men who are present in the flesh by your side; they are the teeth of an appalling lioness that will one day break your bones.” http://www.angelfire.com/md/devere/gildas.html
Lovely stuff. Mark Devere Davies writes further, in reference to the name Arthur as ‘bear': “It has long been recognized that Arthur best translates as “Bear” in Celtic. A marginal note on a 13th century copy of the “Historia Brittonum”, by Nennius(9th century) says that Arthur means “Ursus Horribilis”. No matter what the actual origin of the name, this earliest etymology is important as it shows beyond doubt that the ancients understood “Arthur” to mean “Bear”. A rival theory has been current for years which claims Arthur derives from the Roman Artorius. This is more of a speculation than a theory as no text supports such a reading. The name is always rendered as some variant of the Welsh Arthur, or is Latinized in various ways like Artus, Arturus, or Arturius. And it should be remembered that “Arthur” was most likely not a personal name at this time. The word is unrecorded as a personal name before the end of the sixth and early seventh century, when several “Arthurs” are known.” http://www.angelfire.com/md/devere/urse.html
Din Arth, the Fort of the Bear, was Cuneglas’ home, located in the Kingdom of Rhos, one of the sub-kingdoms of Gwynedd. It was situated above Colwyn Bay on Bryn Euryn. “An oval enclosure was built in the 5th century at the highest point of the fort to form a sturdy inner sanctum. Along with the surrounding Iron Age enclosure, a layout similar to the motte and bailey castles of the Normans was achieved and the same arrangement can be seen just a few miles up the Conwy Valley at Pen-Y-Castell, on a rocky ridge high above the village of Maenan.” http://www.castlewales.com/euryn.html