Adar Rhiannon
In the earliest prose stories in Britain in the Mabinogi, the Adar Rhiannon; "birds of Rhiannon", are specifically three magical birds, whose song can "wake the dead and lull the living to sleep". They also have a non-rational effect on space as they can be remote but seem very near. They are connected with Rhiannon the Queen of Dyfed who is thought to be a British euhemerized horse goddess, so part of Welsh mythology. The Adar Rhiannon were demanded by the giant Ysbaddaden Bencawr as a marriage task for Culhwch to complete. The giant wanted the Birds to soothe him as he faced his last night of life, prophesied as the consequence of his daughter's wedding.
