These correspondences might be pursued in much further detail. It is enough here to point to their existence as evidence of the original community of Gaelic and Cymric mythology.(220) We are, in each literature, in the same circle of mythological ideas. In Wales, however, these ideas are harder to discern; the figures and their relationships in the Welsh Olympus are less accurately defined and more fluctuating. It would seem as if a number of different tribes embodied what were fundamentally the same conceptions under different names and wove different legends about them. The bardic literature, as we have it now, bears evidence sometimes of the prominence of one of these tribal cults, sometimes of another. To reduce these varying accounts to unity is altogether impossible. Still, we can do something to afford the reader a clue to the maze. *The Houses of Dōn and of Llyr* Two great divine houses or families are discernible—that of Dōn, a mother-goddess (representing the Gaelic Dana), whose husband is Beli, the Irish Bilé, god of Death, and whose descendants are the Children of Light; and the House of Llyr, the Gaelic Lir, who here represents, not a Danaan deity, but something more like the Irish Fomorians. As in the case of the Irish myth, the two families are allied by intermarriage—Penardun, a daughter of Dōn, is wedded to Llyr. Dōn herself has a brother, Māth, whose name signifies wealth or treasure (_cf._ Greek Pluton, _ploutos_), and they descend from a figure indistinctly characterised, called Māthonwy. *The House of Arthur* Into the pantheon of deities represented in the four ancient Mabinogi there came, at a later time, from some other tribal source, another group headed by Arthur, the god Artaius. He takes the place of Gwydion son of Dōn, and the other deities of his circle fall more or less accurately into the places of others of the earlier circle. The accompanying genealogical plans are intended to help the reader to a general view of the relationships and attributes of these personages. It must be borne in mind, however, that these tabular arrangements necessarily involve an appearance of precision and consistency which is not reflected in the fluctuating character of the actual myths taken as a whole. Still, as a sketch-map of a very intricate and obscure region, they may help the reader who enters it for the first time to find his bearings in it, and that is the only purpose they propose to serve. *Gwyn ap Nudd*