Turning from the sky-god and his son, we find others of Dôn’s children to have been the exponents of those arts of life which early races held to have been taught directly by the gods to men. Dôn herself had a brother, Mâth, son of a mysterious Mâthonwy, and recognizable as a benevolent ruler of the underworld akin to Beli, or perhaps that god himself under another title, for the name Mâth, which means “coin, money, treasure”,[302] recalls that of Plouton, the Greek god of Hades, in his guise of possessor and giver of metals. It was a belief common to the Aryan races that wisdom, as well as wealth, came originally from the underworld; and we find Mâth represented, in the Mabinogi bearing his name, as handing on his magical lore to his nephew and pupil Gwydion, who, there is good reason to believe, was the same divine personage whom the Teutonic tribes worshipped as “Woden” and “Odin”. Thus equipped, Gwydion son of Dôn became the druid of the gods, the “master of illusion and phantasy”, and, not only that, but the teacher of all that is useful and good, the friend and helper of mankind, and the perpetual fighter against niggardly underworld powers for the good gifts which they refused to allow out of their keeping. Shoulder to shoulder with him in this “holy war” of culture against ignorance, and light against darkness, stood his brothers Amaethon, god of agriculture, and Govannan, a god of smithcraft identical with the Gaelic Giobniu. He had also a sister called Arianrod, or “Silver Circle”, who, as is common in mythologies, was not only his sister, but also his wife. So Zeus wedded Heré; and, indeed, it is difficult to say where otherwise the partners of gods are to come from. Of this connection two sons were born at one birth—Dylan and Lleu, who are considered as representing the twin powers of darkness and light. With darkness the sea was inseparably connected by the Celts, and, as soon as the dark twin was born and named, he plunged headlong into his native element. “And immediately when he was in the sea,” says the Mabinogi of Mâth, son of Mâthonwy, “he took its nature, and swam as well as the best fish that was therein. And for that reason was he called Dylan, the Son of the Wave. Beneath him no wave ever broke.” He was killed with a spear at last by his uncle, Govannan, and, according to the bard Taliesin, the waves of Britain, Ireland, Scotland, and the Isle of Man wept for him.[303] Beautiful legends grew up around his death. The clamour of the waves dashing upon the beach is the expression of their longing to avenge their son. The sound of the sea rushing up the mouth of the River Conway is still known as “Dylan’s death-groan”[304]. A small promontory on the Carnarvonshire side of the Menai Straits, called _Pwynt Maen Tylen_, or _Pwynt Maen Dulan_, preserves his name.[305]