Diane, Dyane, Dyanne
The Roman goddess of the moon, the hunt and childbirth among several other things.
According to the Vulgate Merlin, it was her enchantment, given to Dyonas, that caused Viviane (the Lady of the Lake) to be so alluring to Merlin. The Vulgate Lancelot tells us that she was the Queen of Sicily, but considered a goddess by her foolish pagan subjects.
The Post-Vulgate Merlin continuation describes how she murdered her lover in order to be with another man, but then was beheaded by this man for being a murderess. This occurred at a lake in France, and was thereafter called the Lake of Diana. This lake was the home of the Lady of the Lake, and was the place where Lancelot was raised, giving him his epithet. Diana is mentioned several times in Spenser’s The Faerie Queene. She raised the huntress Belphoebe, who became the paramour of Arthur’s squire, Timias.
Said to be the godmother of Nimue, and to have officiated at a marriage between Nimue and Merlin, after which Nimue kept Merlin in a magic castle.
Sources
Lancelot do Lac | 1215-1220
Vulgate Lancelot | 1215-1230
Vulgate Merlin | 1220-1235
Post-Vulgate Suite du Merlin | 1230-1240
The Faerie Queene | Edmund Spenser, 1570-1599