Vales, Vance
In the Post-Vulgate Merlin continuation and in Malory, King Rions (Ryons), Arthur’s enemy, took the wife of the Duke of the Vaux (“vales”) as his lover.
While riding to visit her one night, Rions was intercepted and abducted by the brothers Balin and Balan, who brought him to Arthur.
Sources
Post-Vulgate Suite du Merlin | 1230-1240
Le Morte Darthur | Sir Thomas Malory, 1469-1470