Dylan ("great tide", from the prefix dy-, "great", or " Reid" which is sometimes associated with "Dylan" and llanw, "tide") Ail Don (Middle Welsh: Dylan Eil Ton) is a sea-god in Welsh mythology, a son of Arianrhod and Gwydion. He is sometimes said to be a god of darkness. Middle Welsh (Cymraeg Canol) is the label attached to the Welsh language of the 12th to 14th centuries, of which much more remains than for any earlier period. ... Welsh mythology, the remnants of the mythology of the pre-Christian Britons, has come down to us in much altered form in medieval Welsh manuscripts such as the Red Book of Hergest, the White Book of Rhydderch, the Book of Aneirin and the Book of Taliesin. ... In Welsh mythology, Arianrhod (silver wheel) was a daughter of Beli and Don. ... In Welsh mythology, Gwydion is a magician appearing prominently in the Fourth branch of the Mabinogi and the ancient poem Cad Goddeu. ...

He was the first of Arianrhod's twins to be born. Since the moment of his birth the golden-haired Dylan was able to swim in the ocean like a fish, and he therefore received the epithet Eil Don (Son of the Wave). His twin brother was Lleu Llaw Gyffes. In Welsh mythology, Lleu Llaw Gyffes (sometimes called Llew Llaw Gyffes) is a character appearing in the fourth of the Four Branches of the Mabinogion, the tale of Math fab Mathonwy. ...

He was killed by his uncle, Gofannon, who didn't know who he was. It was said that his death was widely mourned. The seas crashed against rocks in grief and Taliesin the bard wrote this eulogy, which he entitled Marwnad Dylan Ail Don In the Welsh mythology, Govannon of Gofannon was a smith and the son of the goddess Don. ... Taliesin or Taliessin (c. ...

One God Supreme, divine, the wisest, the greatest his habitation,
when he came to the field, who charmed him in the hand of the extremely liberal.
Or sooner than he, who was on peace on the nature of a turn.
An opposing groom, poison made, a wrathful deed,
Piercing Dylan a mischievous shore, violence freely flowing
Wave of Iwerdon, and wave of Manau, and wave of the North,
And wave of Prydain, hosts comely in fours.
I will adore the Father God, the regulator of the country, without refusing.
Creator in Heaven, may he admit us into merry.