Mention of the recipe reminds me of a story in last week's newspaper. A recipe for what we know as lasagna turned up in an old English book (I think Elizabethan) and this brought out that the recipe was known much earlier than that in some other area. Of course some Italian insisted that these recipes were not for the real lasagna. Can't remember the details.

The earliest printed record is a point of reference- nothing more. It gives us something to shoot at. We know only that the song is at least that old. Other evidence (if any) must then be brought into play. We can examine the internal references (a la Ian) for clues, but we must also remember that the song writer might have known a bit of history and could have written it many years after the event.

Moreover, we only have to read the threads here to find out how easy it is to invent a history for a song and then delude one's self into believing it and insisting that others also believe.