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. Most now know Rhodri's mother as Essylt daughter of Cynan Dindaethwy, last King of the House of Cunedda, and that Nest being married to Merfyn or Rhodri was merely a rumor spread and recorded by supporters of Gwynedd to demean the Kings of Powys and to claim lordship over them. The House of Gwynedd's Kingship is recorded being passed by distaff (Female right) through Essylt to Merfyn her husband and then to their son Rhodri on Merfyn's death, the same going for Rhodri's wife Angharad daughter of Meurig King of Seisyllwg when her brother Gwgon drowned without an heir, which allowed Rhodri to inherit it through his wife by her right and his son Cadell to inherit it from his father by his mother's right.
However the Historical Nest ferch Cadell who was inserted into Rhodri's lineage to push Gwynedd's overlordship of Powys was a daughter of Cadell son of Brochwel II of Powys and was married to Gwerstan son of Gwaithfoed whose Grandson Bleddyn founded the Powysian House of Mathrafal.
- 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.