Eudaf is largely unknown, other than from various royal genealogies where he is known as Eudaf Hen (the old: in Old Welsh his name was apparently Outham Senis [Bromwich* p.548], i.e. possibly Octavius*). In the Welsh Tale "the Dream of Maxen" the Emperor of Rome, Maxen, marries Helen the daughter of the king of Aber Sain, Eudav, who is also listed as the father of Kynan and Adeon, and the son of Caradawc (Caer Seint, his castle = Segontium* = Caernarfon [Details]). There is obviously some confusion in the ordering, either of our genealogy or the one in the Dream.

This confusion is added to by the 12th C. Life of St Gurthiern* which has the following (translated from the Latin):

Then Gurthiern son of Bon son of Glou son of Abros son of Dos son of Iacob son of Genethauc son of Iugdual son of Beli son of Outham Senex son of Maximian son of Constantius son of Constantine son of Helen who was thought to have returned(?) the cross of Christ... Beli was the son of Anne who they say is the cousin of Mary who gave birth to Christ.

This plainly confuses Beli, a potential son of Eudaf in the position of Adeon, with Beli Mawr (See Note on Llyr). Both Eudaf (the son of Maxen, not his father-in-law) and Helen (great-grandmother of Eudaf, not his daughter) appear out of place, but the repetition of names in families is common.

The other notable fact from the Dream is that, after a request from Helen, Maxen gives Eudav the whole of Britain as a gift to rule over.