Sorefingers,

we can notice the "very same theme" of a lot of ballads in much much earlier literature. The cuckolded husband: Chaucer, Boccacio, Apuleius, etc. So theme is not a reliable way to place origins.

Anyway, the point is not where it might have come from in a sort of vacuum, but where the evidence points to. Any traditional song in the English language Might be Irish, but that kind of ruins the point of Jed's exercise.

I find that many people want to believe songs are Irish in origin because they have a political predilection to do so. I personally don't care where a song originated. In these cases, though, the evidence of first texts generally supports an English origin. Granted, collection began in England earlier and printing was more widespread there, so the evidence may not be reliable. But it's all we have.

One thing that IS true: ballads as such are far more characteristic of English and Scots culture than of Gaelic culture, so the ballad tradition is largely an import to Ireland. But Irish folks sure ran with it!