Ceridwen or Cerridwen was an enchantress in Welsh medieval legend. She was the mother of a hideous son, Mordfran, and a beautiful daughter, Creirwy. Her husband was Tegid Foel and they lived near Bala Lake in north Wales. Medieval Welsh poetry refers to her as possessing the cauldron of poetic inspiration (Awen) and the Tale of Taliesin recounts her swallowing her servant Gwion Bach who is then reborn through her as the poet Taliesin. Ceridwen is regarded by many modern pagans as the Celtic goddess of rebirth, transformation, and inspiration.

Welsh mythology consists of both folk traditions developed in Wales, and traditions developed by the Celtic Britons elsewhere before the end of the first millennium. As in most of the predominantly oral societies Celtic mythology and history were recorded orally by specialists such as druids. This oral record has been lost or altered as a result of outside contact and invasion over the years. Much of this altered mythology and history is preserved in medieval Welsh manuscripts, which include the Red Book of Hergest, the White Book of Rhydderch, the Book of Aneirin and the Book of Taliesin. Other works connected to Welsh mythology include the ninth-century Latin historical compilation Historia Brittonum and Geoffrey of Monmouth's twelfth-century Latin chronicle Historia Regum Britanniae, as well as later folklore, such as the materials collected in The Welsh Fairy Book by William Jenkyn Thomas (1908).