Nest ferch Cadell
On the death of her brother Cyngen ap Cadell in 855, authority over the Kingdom of Powys passed to her son Rhodri the Great who had previously inherited the Kingdom of Gwynedd on the death of his father in 844, thereby uniting the Kingdoms of Powys and Gwynedd.
It is unclear why the inheritance of Powys passed through Nest to her son, and not to one of the sons of Cyngen: Elisedd ap Cyngen, Ieuaf ap Cyngen, Aeddan ap Cyngen, and Gruffudd ap Cyngen. The texts of Welsh laws which survive to us were written down no earlier than the 12th century, but they provide no evidence that women were capable of transmitting legal title of kingship or lordship. Equally, although the pedigree in a manuscript in Jesus College Oxford states Nest as the mother of Rhodri the Great, another pedigree in a fourteenth-century manuscript in the National Library of Wales records his mother as Essyllt ferch Cynan. There are no strong grounds to accept either manuscript as reliable, but it is reasonable to believe that the royal house of Gwynedd promoted the view that the Kingdom of Powys had passed to Rhodri the Great through his mother in order to legitimise their control over it. Either way, this possible genealogical manipulation became part of the accepted story of the unification of the two kingdoms.
According to J. Morris, after the death of Mervyn Frych she had a second marriage to Gwerystan ap Gwaithfoed, with whom she had a son, Cynfyn ap Gwerstan. This however, is impossible. As Cynfyn was born c. 990, whereas Nest is already known to have given birth to 'Rhodri the Great' c. 820.
- Jesus College Oxford, Manuscript 20
- National Library of Wales, Mostyn Manuscript 117: Bonedd y Arwyr genealogies.
- Kari Maund (2000). The Welsh Kings: The Medieval Rulers of Wales. Tempus.
- JMorris - Shropshire Genealogies volume 1 page 86.