Even within the Arthurian tales, it is hard to picture the Lady of the Lake clearly; aspects of her turn up in many of the legendary Ladies. In most Arthurian material, she is called Morgan or Morgaine, but in the later French tales, she is also called Viviane and Elaine.

As Morgan le Fay, she is depicted as the enchantress and seductress who arranges Arthur's downfall, but also, paradoxically, as the one who takes him away to Avalon to be healed of his mortal wounds. As "The Lady of the Lake", she holds the sword Excalibur out of the waters for Arthur. As Viviane, she learns magic from Merlin and eventually imprisons him in a tree. As Elaine, she is the mother of Galahad the Grail knight, but as Morgan she is the mother of Arthur's usurping illegitimate son. She appears too as the keeper of the most Holy Grail.

What does all this mean? How can she be at the same time both good and evil? The answer lies not in the Lady as she appears in the Arthurian tales, but in her earlier forms as Brigid and Ceridwen.