Understanding the descent of the kings of Powys poses considerable problems. These can be resolved when it is realised that the sons attributed to Vortigern (Gwrtheyrn Gwrtheneu) are in reality the offsprings of Cadell Ddyrnllug. The reason behind this intentionally incorrect attribution is given in HB 32-35. It tells how the royals of Powys were descendants of Cadell whose origins were humble. HB 34 tells us Cadell had nine sons. The Harleian manuscript gives the names of five of them, although they are incorrectly listed not as siblings but as sons of each other:
The Pillar of Eliseg mentions four of the sons:
CONCE[NN] PASCEN[T] MAU[N] ANNAN [+] BRITU
The third and fourth elements of this part of the inscription is a reference to a single name, i.e. Mawgan. It is claimed the PE states they were the sons of Gwrtheyrn. However, this may be a misreading and the above four names were not being linked to Gwrtheyrn but rather to the largely missing previous lines. Following the above text the inscription reads:
A[ ]T[ ]M FILIUS GUARTHI[ ] QUE(m) BENED[ ] GERMANUS
HB 48 tells us that Gwrtheyrn’s son, Faustus, by his incestuous relation with his daughter, was brought up by Germanus. So, the first word in the above text may be a reference to Faustus, the only genuinely known son of Gwrtheyrn. This interpretation is supported by the use of the singular form ‘filius’.
ABT 6k1, shown below, matches the above HG 27:
|-2||Cadell Ddyrnllug||Pasgen||Brydw||Rhuddfedel Frych||Cyndeyrn|
Although the manuscript states Nest was the mother of Merfyn Frych the above table shows her as his wife. This is indicated as being the case in JC 18.
ABT 6k2 promotes the myth that, except for Cyngen, the sons of Cadell were, in reality, the sons of Gwrtheyrn. As noted by Phillimore the name Cateyrn has been ‘tortured’ into the form Cyndeyrn by later genealogies. Vermaat explains the presence in the list of Rhuddfedel as a reference to the battle at Rithergabail where Cateyrn died.
 Cy IX, 179 n. 5
 Vortigern Studies > Vortigern > The Family of Vortigern > Catigern, son of Vortigern