 ), sometimes called Rhyddfedd ap Categern was, according to the genealogical lists, a late 5th century King of Powys, Wales.His actual date of birth is uncertain, as is his date of death and the date he ascended to the throne.The name of his father, Categern (=Cadeyrn), has led some scholars to speculate that he was the son of Cadeyern Fendigaid, and thus brother to Cadell Ddyrnllwg, who preceded his kingship.