Ethyllt ferch Cynan

Esyllt ferch Cynan Dindaethwy was an eighth century princess of the Kingdom of Gwynedd in North Wales. She was the daughter of King Cynan Dindaethwy ap Rhodri of Gwynedd.

Marriage and dynastic descents Esyllt ferch Cynan was an eighth century princess of the Kingdom of Gwynedd in North Wales. At some point, she was married to Gwriad ap Elidyr, also known as Gwriad Manaw. It is possible this was a later invention to legitimise the claims to Gwynedd by the descendants of Merfyn Frych King of Gwynedd from c. 825 to 844.

According to some source Merfyn was Esyllt's son, in others he was her husband, which then made Esyllt the mother of Rhodri Mawr (Rhodri the Great) although Nest ferch Cadell, daughter of Cadell ap Brochfael of the Kingdom of Powys is considered a more likely candidate for this role.

Whichever the case, Esyllt was a key matriarchal figure for the royal houses of Gwynedd and Deheubarth in Wales in the Early Middle Ages, giving a matrilineal link of descent to the line of King Cunedda. On Hywel's death, the throne was claimed by Merfyn Frych with his descent via Esyllt playing a part in his claim to the throne.