Thanks, Alan, for reminding me of the early mention of the (or "a similar") title. It may, however, allude instead to the very different song of "Tam o the Linn."

And Jim, "what was in print" is far from being a complete guide, but it is better than no guide at all. If something was in print, at least we know it existed. Enthusiasts sometimes assume that ballads are almost timeless artifacts, centuries older than their first known appearance and (it sometimes seems) hardly changed since then. That approach is just as misleading (though far more fun) than insisting on a printed text before allowing the possibility of a song's existence.

Even Henderson gets carried away. He talks about the Johnstons "living out elemental ballad themes in South-West Scotland long before Robert Burns was born." Perhaps, but here it more or less suggests that they were singing "Tam Lin" long before Burns was born, too. Whether they were or not is quite unknown.