Caradoc of Cambria
He conquered Ireland and married the king’s daughter, by whom he had two children: Meriadoc and Orwen.
As he grew old and infirm, he gradually relinquished control of his kingdom to his brother, Griffin, retaining only the ceremonial title for himself. Griffin, however, grew covetous of the throne and had Caradoc assassinated during a hunt. Meriadoc escaped to Arthur’s court and later brought justice to Griffin.
Source
Historia Meriadoci Regis Cambrie | Late 13th century