Editing Math fab Mathonwy (section)

===Gwydion and his nephew===
After their punishment was over, Math asked their advice as to who should be his next virgin footholder. Gwydion suggested his sister, [[Arianrhod]]. However, Arianrhod was not a virgin, and when asked to step over Math's rod in order to prove her virginity she immediately gave birth to a son. Abandoning the child she fled in shame, letting drop a "lump of flesh" which was borne away by Gwydion and concealed in a chest. When Gwydion later opens the chest he discovered the lump of flesh to be a second child.

Meanwhile, the firstborn son of Arianrhod was acknowledged by his great uncle Math and given the name ''Dylan'' upon baptism. However, as soon as Dylan came in contact with his baptismal waters, he plunged into the sea and took on characteristics of a sea creature, moving through the seawater as perfectly as any fish, thus earning his new name, [[Dylan ail Don]], "Dylan second wave": "So they had the boy baptized, and as they baptized him he plunged into the sea. And immediately when he was in the sea, he took its nature, and swam as well as the best fish that was therein."<ref>Guest, 1877: Ch. 9</ref>

The unnamed second child grew precociously and he and Gwydion grew very attached to one another. After four years Gwydion took the boy to see his mother, who refused to recognise him out of shame and anger that Gwydion should have nurtured the boy, and placed a ''[[tynged]]'' on him that he should have no name unless she gave it to him. To trick her into naming him, Gwydion disguised himself and the boy as shoemakers and as they were making shoes for her, the boy threw a stone at a bird and killed it. Arianrhod declared "The fair one struck with a deft hand", and thus he was named [[Lleu Llaw Gyffes]], "Fair-Haired One of the Skillful Hand".

His trick revealed, Arianrhod placed a ''tynged'' on the boy again that he would not take up arms until she gave them to him. Time passed and Lleu grew big and strong. Again, Gwydion disguised his nephew and himself, this time as bards, and like he did to King Pryderi, entertained Arianrhod's court with stories. In the morning, Gwydion deceived Arianrhod to believe that her estate was under attack. When she asked for his advice, he bade her gird a sword on Lleu Llaw Gyffes, who he said was a skilful fighter. No sooner had she done so than Gwydion revealed the truth.

Furious at being tricked again, Arianrhod placed a ''tynged'' on her son once more, that he would never have a human wife. By this time, Math had come to sympathize with Gwydion. Together, they created a woman from the flowers of the oak, broom and meadowsweet and brought her to life, giving her the name [[Blodeuwedd]] "Flower-Faced".