Helaine, Heleyne, Nimiane, Niniame, Ninniane
The Lady of the Lake in the Vulgate Lancelot and the Post-Vulgate Merlin continuation. She raised Lancelot and imprisoned Merlin.
The Middle English Prose Merlin says that the name was Hebrew, meaning “I shall not lie”. Arthour and Merlin, which gives the Lady of the Lake role to Morgan le Fay, names Ninniane as a town near Morgan’s residence.
Some scholars have favored a Celtic origin for Ninniane, finding it in the lady Rhiannon, wife of Lord Pwyll.
Merlin calls her Nimue.
Sources
Vulgate Lancelot | 1215-1230
Le Livre d’Artus | Early 13th century
Post-Vulgate Suite du Merlin | 1230-1240
Arthour and Merlin | Late 13th century