Mary O’ The Wisp reel

A great tune that I’m guessing is from Donegal. Lots of bowed triplets and a driving rhythm make it great for the fiddle.

This tune is NOT Moll na Tiarna, despite what on the Altan album notes, but a companion tune called Mary o’ the Wisp. The two tunes are very frequently played together in Donegal as the names come from an old folk-tale, where Mary o’ the Wisp is the servant of Moll.

They play the same tune on Blackwater. I know it as Biddy From Muckross

bar the last high b, this mighty reel suits the Highland pipes perfectly.

X: 1
T: Moll And Tiarna
M: 4/4
L: 1/8
R: reel
K: Dmaj
Ad d2 efdB|Ad d2 efdB|ABde fAde|fage fddB|
Ad d2 efdB|Ad d2 efdB|ABde fAdB|1cA A2 cA A2:|2cA A2 cdeg||
faga faga|fage fdde|faga fefg|eA A2 efge|
faga faga|fage fefg|abag efed|1cA A2 cdeg:|2cA A2 cA A2||

To Prouse :
If this tune is not Moll na Tiarna, then what is the right tune under this title ?

The tune here is "Maire na Sop," also called "Mary of the Wisp." Altan’s source for the tune might have been Francie Dearg Byrne, who played it followed by a tune he called "Moll na Tiarna"—the latter appears to be a version of "The Volunteer."

Regarding Prouse’s comment from 13 years ago, does anyone have information on the folktale for which these two tunes are named? I’m very curious; I tried checking online but have had no luck so far.