Merfyn Frych

[3] Merfyn came to the throne in the aftermath of a bloody dynastic struggle between two rivals named Cynan and Hywel – generally identified with the sons of Rhodri Molwynog.

Both kingdoms were beset by internal dynastic strife, external pressure from Mercia, and bad luck with nature.

A destructive war for control of Gwynedd raged between 812 and 816, while in Powys a son of the king was killed by his brother "through treachery".

Coastal Wales along the Dee Estuary must have remained under Mercia's control through 821, as Coenwulf is recorded dying peacefully at Basingwerk in that year.

King Beornwulf was killed fighting the East Anglians in 826, his successor Ludeca suffered the same fate the following year, and Mercia was conquered and occupied by Ecgberht of Wessex in 829.

Though Mercia managed to throw off Ecgberht's rule in 830, it was thereafter beset by dynastic strife and never regarded its former dominance, either in Wales or eastern England.

[12][13] Supporting the veracity of the pedigree is an entry in the Annales Cambriae, which states that Gwriad, the brother of Rhodri Mawr, was slain on Anglesey by the Saxons.