The Outlandish Knight is included under #4 in the Child cannon (Lady
Isable and the Elf
Knight). The closest variant in Child (1882-1898)CPB seems to be #4E
(vol I, pp58-59). Indeed, apart from the odd word, they are almost
identical.
Titles for the alternative versions include "May Colvin, May
Collean", and "False Sir John". Both Scottish and English versions are
to be found.
According to Kidson, "The "Outlandish Knight" is the English copy of
the story, and it was first edited in a volume issued by the Percy
Society, by Mr. J. H. Dixon; Scottish
Traditional Versions of Ancient Ballads, 1846." Incidentally,
Child gives J. H. Dixon as the source for #4E; Ancient Poems, Ballads, and Songs of the
Peasantry of England, p74.
Regarding the air, it "was obtained in the North Riding of
Yorkshire, and is certainly an early tune."
A brief note on typographical errors; should any be spotted, please
let me
know! That said, the quote marks in the second stanza are as Kidson's
book - the verse starts with a double quote, but finishes with a single.