Rhodri Mawr – Rhodri the Great – succeeded to the throne of Gwynedd upon the death of his father Merfyn Frych in 844. Later sources describe him as ‘King of Wales’, though Rhodri never used the title himself and never added South Wales to his kingdom. He did, however, extend his realm further than any Welsh leader before him. Through his mother he inherited Powys, in mid-Wales, in 855, and through marriage he eventually also added Seisyllwg – the land south of Gwynedd as far as the Gower Peninsula. His wife Angharad was the sister of Gwgon, the previous ruler of Seisyllwg, who drowned in 871. What role, if any, Rhodri played in his untimely death is unclear.
Rhodri was a successful warrior, fighting wars and defending his lands on several fronts during his 44-year reign. In 854 the Vikings launched an attack on Anglesey, the traditional seat of power for the rulers of Gwynedd. Two years later Rhodri met them in battle and killed their leader, Gorm (or Horm), a deed for which he was celebrated in verse. On the eastern front of his realm he had to fight off the Anglo-Saxons of Mercia, and it was in a battle with them in 878 that he was killed, along with one of his sons.
Four sons remained, however, and Rhodri’s extensive kingdom was divided among them after his death. To be descended from Rhodri was considered an important qualification for future princes of Gwynedd.