Branwen, “White Bosom,” daughter of a sea-god, may be a sea-goddess, “Venus of the northern sea,"[359] unless with Mr. Nutt we connect her with the cauldron described in her legend,[360] symbol of an orgiastic cult, and regard her as a goddess of fertility.  But the connection is not clear in the story, though in some earlier myth the cauldron may have been her property.  As Brangwaine, she reappears in romance, giving a love-potion to Tristram—­perhaps a reminiscence of her former functions as a goddess of love, or earlier of fertility.  In the Mabinogion she is buried in Anglesey at Ynys Bronwen, where a cairn with bones discovered in 1813 was held to be the grave and remains of Branwen.[361]

The children of Don, the equivalent of Danu, and probably like her, a goddess of fertility, are Gwydion, Gilvaethwy, Amaethon, Govannon, and Arianrhod, with her sons, Dylan and Llew.[362] These correspond, therefore, in part to the Tuatha Dea, though the only members of the group who bear names similar to the Irish gods are Govannon (= Goibniu) and possibly Llew (= Lug).  Gwydion as a culture-god corresponds to Ogma.  In the Triads Beli is called father of Arianrhod,[363] and assuming that this Arianrhod is identical with the daughter of Don, Professor Rh[^y]s regards Beli as husband of Don.  But the identification is far from certain, and the theory built upon it that Beli is one with the Irish Bile, and that both are lords of a dark underworld, has already been found precarious.[364] In later belief Don was associated with the stars, the constellation Cassiopeia being called her court.  She is described as “wise” in a Taliesin poem.[365]

This group of divinities is met with mainly in the Mabinogi of Math, which turns upon Gilvaethwy’s illicit love of Math’s “foot-holder” Goewin.  To assist him in his amour, Gwydion, by a magical trick, procures for Math from the court of Pryderi certain swine sent him by Arawn, king of Annwfn.  In the battle which follows when the trick is discovered, Gwydion slays Pryderi by enchantment.  Math now discovers that Gilvaethwy has seduced Goewin, and transforms him and Gwydion successively into deer, swine, and wolves.  Restored to human form, Gwydion proposes that Arianrhod should be Math’s foot-holder, but Math by a magic test discovers that she is not a virgin.  She bears two sons, Dylan, fostered by Math, and another whom Gwydion nurtures and for whom he afterwards by a trick obtains a name from Arianrhod, who had sworn never to name him.  The name is Llew Llaw Gyffes, “Lion of the Sure Hand.”  By magic, Math and Gwydion form a wife for Llew out of flowers.  She is called Blodeuwedd, and later, at the instigation of a lover, Gronw, she discovers how Llew can be killed.  Gronw attacks and wounds him, and he flies off as an eagle.  Gwydion seeks for Llew, discovers him, and retransforms him to human shape.  Then he changes Blodeuwedd into an owl, and slays Gronw.[366] Several independent tales have gone to the formation of this Mabinogi, but we are concerned here merely with the light it may throw on the divine characters who figure in it.