Blodeuwedd (in Welsh pronounced as /blɔˈdɛɨwɛð/; Welsh "Flower-Faced", a composite name from blodau "flowers" + gwedd "face"),[1] is married to Lleu Llaw Gyffes in Welsh mythology. She was made from the flowers of broom, meadowsweet and oak by the magicians Math and Gwydion, and is a central figure in Math fab Mathonwy, the last of the Four Branches of the Mabinogi.
The hero Lleu Llaw Gyffes has been placed under a tynged ("doom") by his mother, Arianrhod, that he may never have a human wife. To counteract this curse, the magicians Math and Gwydion:Some time later, while Lleu is away on business, Blodeuwedd has an affair with Gronw Pebr, the lord of Penllyn, and the two lovers conspire to murder Lleu. Blodeuwedd tricks Lleu into revealing how he may be killed, since he cannot be killed during the day or night, nor indoors or outdoors, neither riding nor walking, not clothed and not naked, nor by any weapon lawfully made. He reveals to her that he can only be killed at dusk, wrapped in a net, with one foot on a bath and one on a black goat, by a riverbank and by a spear forged for a year during the hours when everyone is at Mass. With this information she arranges his death.
Struck by the spear thrown by Gronw's hand, Lleu transforms into an eagle and flies away. Gwydion tracks him down and finds him perched high on an oak tree. Through the singing of an englyn (known as englynion Gwydion) Gwydion lures Lleu down from the oak tree and switches him back to his human form. Gwydion and Math nurse Lleu back to health before mustering Gwynedd and reclaiming his lands from Gronw and Blodeuwedd.
Gwydion overtakes the fleeing Blodeuwedd and turns her into an owl (in Welsh tylluan or gwdihŵ), the creature hated by all other birds, proclaiming:The narrative adds:Meanwhile, Gronw escapes to Penllyn and sends emissaries to Lleu, to beg his forgiveness. Lleu refuses, demanding that Gronw must stand on the bank of the River Cynfael and receive a blow from his spear. Gronw desperately asks if anyone from his warband will take the spear in his place, but his men refuse his plea. Eventually, Gronw agrees to receive the blow on the condition that he may place a large stone between himself and Lleu. Lleu allows Gronw to do so, then throws the spear with such strength that it pierces the stone, killing his rival. A holed stone in Ardudwy is still known as Llech Ronw (Gronw's Stone).
Robert Graves and others consider lines 142–153 of Cad Goddeu to be a "Song of Blodeuwedd".