The two names Custennin Fendigaid, that of the brother of Aldwr, and Custennin Gorneu refer to the same individual. Bartrum wrote, concerning ByS 76:
“Thus Custennin Gorneu and Custennin, the grandfather of Arthur, have been tacitly identified. Further confirmation of this is the fact that Erbin ap Custennin is said to have been uncle to Arthur, and Geraint ab Erbin first cousin to Arthur in the tale of ‘Geraint and Enid’ …”
The following table confirms this identification:
|Gen.||ChB||ByS 26||ByS G 24a|
|1||Hoelus Secundus||Kyby||Howel vychan|
The names in the above table are as they appear in the document. Note, ByS 26 has been adjusted to show Cybi as being the son of Selyf ab Erbin as indicated by his Vitae. Budic was referred to as Emyr Llydaw. This can be confirmed by looking at parallel entries in the HRB and the ByB. However, chronology indicates that the Breton king with whom Uthr and Ambrosius found refuge was Budic ap Cybrdan.