Morgan Le FayFrom Brewer's Dictionary of Phrase and Fable
The fairy sister of King Arthur, a principal figure in Celtic legend and Arthurian romances, also known as Morgane, Morgaine, Morgue la Faye and as Morgana. Her name is of very uncertain origin, as are many names of Celtic mythology. It may come from Breton Morigena, ‘born of the sea’, or else Gaulish mawr, ‘great’, and can, ‘shining’. Some say it means ‘dawn’, and so relate it to English ‘morning’. Finally, there is the school that traces it back to Arabic marjan, ‘coral’, from Greek margaris, ‘pearl.’