Arianrhod

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. Gilfaethwy conceives a lust for Math's original footholder, pretty Goewin, and he and his brother Gwydion engineer a war with King Pryderi of Kingdom of Dyfed, forcing Math to leave his court. In Math's absence Gilfaethwy rapes Goewin. 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. However, he must find a new virgin to hold his feet.

Gwydion suggests his sister, Arianrhod. To test her virginity, Math tells her to step over his magician's rod. On doing this, however, she immediately gives birth to a young boy, Dylan ail Don, and a blob-like entity which becomesLleu Llaw Gyffes. Dylan is a sea spirit, who immediately flees to the ocean. Gwydion grabs Lleu Llaw Gyffes before anyone else sees it and places it in a chest. Before long it becomes a boy who grows at twice the normal rate; when he is four he is as big as an eight-year-old. Gwydion takes him to see his mother at her home, Caer Arianrhod.

However, Arianrhod was angry about her humiliation at Math's court. She places a tynged (a geis or taboo) on the boy that he will never have a name unless she gives it to him. Gwydion disguises the boy as a shoemaker and returns to Caer Arianrhod; while Arianrhod is being fitted, she sees the boy killing a wren with a single stone and remarks that the fair-haired one ("lleu") has a skillful hand ("llaw gyffes"). Gwydion reveals the disguise, and says she has just given her son a name – Lleu Llaw Gyffes. Arianrhod then places a second tynged on Lleu, that he would never take arms unless she armed him. A few years later Gwydion and Lleu return to Caer Arianrhod, this time disguised as bards. Gwydion is an accomplished storyteller and entertains her court. That night, while everyone sleeps, he conjures a fleet of warships. Arianrhod gives her guests weapons and armor to help her fight, thereby dispelling her second curse. When Gwydion reveals the trickery, Arianrhod places a final tynged on Lleu: he would never have a wife from any race that is on this earth now. Gwydion and Math eventually break this curse by creating a woman out of oak blossom, brrom, and meadowsweet; she is named Blodeuwedd ("flower face").

With her curses, Arianrhod denied Lleu the three aspects of masculinity: a name, arms, and a wife.

Source: Wikipedia