Gwydion

Probably means "born of trees" from Old Welsh guid "trees" and the suffix gen "born of". In the Fourth Branch of the Mabinogi [1], Gwydion is the nephew of King Math of Gwynedd, and like him a powerful magician. In an elaborate plot to give his brother a chance to rape his uncle's footbearer, he arranged a war between Gwynedd and the neighbouring kingdom of Dyfed. Gwydion himself killed King Pryderi of Dyfed at the end of the war. In punishment for the rape, Math transformed Gwydion and his brother into different animals over the course of three years. Gwydion was the uncle of Lleu Llaw Gyffes, whom he fostered. Math and Gwydion fashioned Lleu a wife, Blodeuwedd, out of flowers and they later aided him after her betrayal. Gwydion also appears in older Welsh poetry such as the Book of Taliesin.