[2] In the Mabinogi her uncle Math ap Mathonwy is the King of Gwynedd, and during the course of the story she gives birth to two sons, Dylan ail Don and Lleu Llaw Gyffes, through magical means.
According to the Fourth Branch (circa 12th century), Arianrhod's uncle Math fab Mathonwy would die if he didn't keep his feet in the lap of a virgin when he was not at war.
When Math returns, he punishes his nephews severely by turning them into a series of mated pairs of animals and marries Goewin to alleviate her shame.
On doing this, however, she immediately gives birth to a young boy, Dylan ail Don, and a blob-like entity which becomes Lleu Llaw Gyffes.
Gwydion and Math eventually break this curse by creating a woman out of oak blossom, broom, and meadowsweet; she is named Blodeuwedd ("flower face").
[citation needed] One of the Welsh Triads, 35 by Rachel Bromwich's numbering, establishes a different family connection for Arianrhod.
This triad is the only source connecting Arianrhod to Beli Mawr and the Caswallawn saga, but it is not incompatible with the tradition recorded in the Mabinogion.
Welsh scholar William John Gruffydd noted that 15th- and 16th-century poets apparently knew an alternate tradition in which Arianrhod actually became Math's footholder.