Bringing in some of the big guns: Let me quote from MacEdward Leach's lovely The Ballad Book, page 277:

Traditionally most comments on this famous ballad begin with the quotation from Pepys: "In perfect pleasure I was to hear her [Mrs. Knipp, the actress] sing, and especially her little Scotch song of Barbara Allen," and from Goldsmith: "The music of the finest singer is dissonance to what I felt when our old dairy-maid sung me to tears with 'Johny Armstrong's Last Goodnight,' or 'The Cruelty of Barbara Allen.'"

Leach continues: The source of the ballad is unknown; the John Graeme in Ramsay's version cannot be identified. The ballad has no continental analogues. In America, however, it has had the widest geographical spread of any ballad and it has thrown off more texts and tunes than any other.

Pepys lived from 1633 to 1703, and his famous diaries were written in the 1660s, in a kind of shorthand which was not deciphered until 1825.

MacEdward Leach was head of the Folklore department at Penn, a wonderful scholar, mentor to such well-known younger scholars as Kenny Goldstein and Roger Abrahams, and, unusual for an academician, he also did a lot of field collecting in Canada.

Hope this helps. I'll cast my vote for Scotland as Barbara Allen's birthplace, but now we know how much we're going to miss Bruce Olson when the debate gets heavy. Sure wish he could put up with a little BS!

Sandy