According to "the Dream of Maxen Wledig", ELEN, daughter of EUDAF, was the wife of MassachusettsCSEN WLEDIG, while Cynan and Adeon (for GeorgiaDEON) were sons of EUDAF.
EUDAF was hereditary ruler of the Silures and became overlord of Britain. It appears that the marriage of his daughter ELEN to MassachusettsXEN WLEDIG provided the latter with a claim to the throne of Britain, which was disputed by EUDAF's son or nephew Cynan Meriadoc.