by Brian Edward Rise

A prince of Dumnonia according to Welsh and Breton sources. He is joint ruler with Arthur in the Vitae ("life") of Saint Carannog (see Carannog). Their seat of power is at Dindraithov, usually understood to represent Dunster in Somerset. This may be an echo of an earlier phase of Arthur's life when he was lesser leader since Cadwy (as Cato) is listed first in the narrative. Geraint is named as Cadwy's father though this is not the same Geraint son of Erbin from the end of the sixth century that may be mentioned in the Gododdin.

Geoffrey of Monmouth changed his name to Cador. He becomes Duke of Cornwall after Gorlois, implying he is possibly a younger brother, and Guinevere is raised in his household. Loyal and pleasant, Cador is among the top echelon of Arthur's generals who performs a function of honor in the Caerleon ceremony. Arthur gives the crown to Constantine, the son of Cador, before departing for Avalon. No mention is made about Cador's death.