King of Northumberland and one of the kings in the first wave of rebellion against Arthur, Clariance pledged 3,000 men of arms to the cause and fought in the battle of Bedegraine. Apparently he became a companion of the Round Table, for he listed among those at the attempted healing of Sir Urre.
Probably he is to be identified with the “King of Northumberland” who appears, for instance, at Arthur’s Candlemas tournament after Elaine of Astolat’s death, to which he brings a hundred good knights and where he gives Hoel of Brittany a fall, and with the King of Northumberland who is father to Sir Epinegris.
Vulgate VII tells of a king or ally of the Sesnes named Clarion. He is probably distinct from Clariance of Northumberland.