Board Thread:Show-Related Questions and Answers/@comment-26151936-20151203000651/@comment-1894786-20151203004827

In Arthurian legend, there were two Ladies of the Lake. Nimue (Merlin's lover/Lancelot's mother) and an unnamed Lady who gives Excalibur to Arthur (Excalibur is NOT the sword in the stone as is widely believed).

In Once, Nimue has no connection to lakes, but there still remains two ladies of the lake: the Siren of Lake Nostos, based off of Greek Mythology. And Lancelot's mother who was first mentioned in "Lady Of The Lake". Lancelot's unnamed mother raised him by the shores of a lake.