Cyfeilliog

Edward's assistance is regarded by historians as evidence that he inherited the overlordship of his father, Alfred the Great, over the south-east Welsh kingdoms.

Cyfeilliog is probably the author of a cryptogram (encrypted text) which was added as a marginal note to the ninth-century collection of poetry known as the Juvencus Manuscript.

[3] Mercia, the Anglo-Saxon kingdom on the eastern Welsh border, had claimed hegemony over most of Wales since the early ninth century.

He is included in a list of abbots of Llantwit said to have been in a "very decayed and rent" parchment discovered in about 1719, but as the source for the document was the forger Iolo Morganwg, it is uncertain whether it was genuine.

The historian Patrick Sims-Williams comments that the fact that Cyfeilliog is not mentioned in any charter before he became a bishop "leaves open the possibility that he really is the Camelauc listed among the abbots of Llantwit, dubious though the source is".

Historians are uncertain of the validity of the list, but as southern Welsh kings accepted Alfred's overlordship in the 880s, acknowledgement of the primacy of Canterbury by bishops at this time would not be unlikely.

[18] Cyfeilliog is included in this succession, but his bishopric covered a much smaller area, and the locations of land grants to him suggest that he was mainly active in Gwent.

[21] In this period, Ergyng was Welsh in language and custom, but under English rule, and he may have ministered to people there with the approval of the Bishop of Hereford.

[23] The earliest charter is probably one dating to around 885: King Hywel ap Rhys of Glywysing gave Cyfeilliog two slaves and their progeny for the souls of his wife, sons and daughters.

The Asser who was the biographer of Alfred the Great spent a year ill in Caerwent at this time, and he may have attested the charter while temporarily attached to Cyfeilliog.

[28] Other donors included Hywel's son Arthfael, who in about 890 granted Villa Caer Birran, at Treberran, Pencoyd, with four modii of land to Cyfeilliog.

Cyfeilliog was awarded an "insult price" "in puro auro" (in pure gold) of the worth of his face, lengthwise and breadthwise.