Arianrhod

In the Fourth Branch of the Mabinogi Arianrhod is presented as a member of Dôn's family who is brought to the court of Math ap Mathonwy to act as footholder. When Math tests her virginity by asking her to step over his magician's rod she immediately gives birth to two children: Dylan ail Don, who goes to the sea, and a shapeless entity that Gwydion later fashions into the boy who becomes Lleu Llaw Gyffes. In a Welsh Triad an alternate genealogy names Beli Mawr as her father; later poetic and modern commentators have sometimes reinterpreted her as a goddess-figure, though those identifications are interpretive rather than explicit in the Mabinogi text.

The medieval Mabinogi gives no sustained physical portrait of Arianrhod; her presence is marked by her household Caer Arianrhod and by the narrative actions she performs. Modern neopagan and literary sources sometimes depict her with motifs suggested by her name (silver, wheels, lunar imagery) but these iconographic elaborations are later interpretations not described in the medieval text.

In the Fourth Branch Arianrhod performs acts with narrative-effective force: the supernatural births triggered by stepping over Math's rod and the placing of tynged (taboo/doom) on her son Lleu — specifically that he shall not receive a name, arms, or a wife except by her allowance. These utterances function as binding pronouncements within the tale. The sources also show her entanglement in court ritual (the role of footholder) and her relation to otherworldly offspring (Dylan as a sea-being). Modern fictional sources sometimes attribute additional magical powers to characters named Arianrhod, but those are later appropriations distinct from the Mabinogi account.