 Cyngen was the last of the original line of kings of Powys.He had three sons, but on his death Powys was annexed by Rhodri Mawr, ruler of Gwynedd.Certain later manuscript pedigrees (like Jesus College 20) claim that Rhodri was the son of Cyngen's sister, Nest ferch Cadell, although others (like Mostyn 117) claim he was the son of Essyllt ferch Cynan (thought to be the daughter of Cynan Dindaethwy, of Gwynedd).