Lady Isabel and the Elf Knight is an adaption of a folk ballad which uses material from other elf-knight ballads and a folk tale called The Black Bull of Norroway to create a hybrid tale.

Isabel’s journey to the three castles is drawn from The Black Bull of Norroway, while the Elf Knight’s attempts to drown her in three separate bodies of water are drawn from different versions of the Lady Isabel/May Collin ballad and its close cousins, in which the protagonist is variously led to a tree in the woods, a woodland river, a well, a spring, or to the shore of the sea. In our discussion of the tale, we refer to this storyy as a 'Bluebeard'-type tale, referring to the infamous tale (popularized by Charles Perrault) in which a newly wed bride discovers a secret chamber in her husband's castle which is filled with the bodies of his former wives. Some of the scholarly discussions of the Isabel ballads deny a connection between the tales, however the shared archetypical elements of the seductive male stranger who takes away a wealthy heiress as a bride, with the real intent of murdering her and taking her riches, as well as the intervention of male relatives to rescue or revenge her in Hind Etin, are undeniable.
 

IN FOLK SONG
 

There are at least three ballad types that deal with the theme of a maiden at odds with a supernatural suitor, variously identified as a stranger, as 'outlandish' or as an 'elf' or 'elfin knight'. Some versions substitute the devil.  The main thrust of our tale is based on the ballad known as Lady Isabel & The Elf Knight or The Outlandish Knight, which tells the tale of the murderous abductor. 'The Elfin Knight' and ballads of its type pit a maiden against a similar elf, fairy or stranger in a contest of riddles, in which winning either suggests the maiden's winning of the elfin lover or defeats his advances and protects her maidenhood. The same riddles are recited in the Scarborough Fair ballad, indicating that one of the lovers may be a supernatural beau. The third type of ballad, 'A Noble Riddle Wisely Expounded', gives the maiden in the pursuer role, seducing the stranger in her own father's house, and answering his riddles to win his promise of marriage after they sahre a bed.  The riddles used in our tale are drawn from the Elfin Knight variant rather than A Noble Riddle Wisely Expounded - but this version is worth listening to as well!