A Druidic goddess, patroness of priestesses, who lived on an island usually identified as Avalon with her nine sisters, who included Moronoe, Mazoe, Gliten, Glitonea, Cliton, Tyronoe and Thitis.
There can be little doubt that Morgen is the original of the Arthurian Morgan Le Fay, although she herself seems to have her origins in Modron, who, in turn, has her origins in Matrona. One account says that she was a historical person who married Urien of Rheged and bore Morfudd and Owain (Ywaine).
Giraldus Cambrensis refers to her as a dea phantistica (imaginary goddess), although earlier sources say she was the master of the healing arts, could fly on artificial wings and could change her shape. It was once believed that Morgen, and subsequently the Arthurian Morgan Le Fay, originated in the Irish Mórrighan, but this has now been almost universally discounted.
Her name change may have been effected in Brittany, where there was a belief in a class of water-fairies known as Morgan(s), or more correctly Mari-Morgan(s). They also believed in one particular Morgan, known as Dahut or Ahes, who, it was said, caused the destruction of the legendary city of Ys.
With such a diverse origin it is not difficult to see why so many attributes were added to her character when later romancers made her the incestuous sister of King Arthur, a magician on a par with Merlin, but malevolent rather than benevolent.
See also
Druids | The Legend of King Arthur