Everyone had heard of the Lady of the Lake, and if asked, would probably locate her at Glastonbury. However, many lakes and rivers in Wales, and at least one in Cornwall, are inhabited by mysterious maidens, the Gwragedd Annwn (the Wives of the Underworld). Many of them own herds of cows rather than magic swords.
Presentation on the Archipelacon 2 Academic Track: the Fafnir Anniversary Symposium.