I learned this song back in the 1960s from Finnuala MacLochlainn, then of Dublin, now of Galway. She is a wonderful singer in English and Gaelic. I forget where she got "Jimmy Murphy" from but back then the song was considered quite rare. The context in which she underestood the song was that of the old tradition of the rape "courtship." The girl, kidnapped and raped, would usually be forced into marriage with her abductor, who got her and her dowery. It was a way for half-mounted gentlemen to get a leg up in the world. (There are Scottish border balleds on this theme, such as "Eppie Morry.") As I found out in my own researchs, in the late eighteenth-century Kilkenny incidents such as these were all too common. So they began hanging the perpetrators, at which point the rape courtship began to go out of fashion. Sadly, it is all too common in some parts of the world today.