Apologies if I've missed something here but. As far as I'm getting the tale, the original version was a poem (presumably no tune) and by the time Robbie MacMahon got hold of the original words, it was married to a tune and it seems already been popularised well enough for people to know there was a "wrong" version. Any suggesetions how the song got into circulation and, is the tune trad or does it have an author?

Jon