Thanks, Mick and Jack, for the extra information.

Now that I've this extra information and it seems the song may well have been fairly or completely new in 1665/6, I have been ruminating on the story. Since, in the earliest known broadside version, there is no indication of a relationship already underway between the unnamed would-be lover of Barbara Allen, this would make her already reluctant to go to his death bed. This may also be accounted for what he was dying of, something folk song commentators seem strangely to miss. This ballad was referred to by Pepys in 1666, and has the ill man's implied inability to get out of bed. Add to that the later versions references to the man's sweating and bleeding and we have three symptoms of the bubonic plague: lethargy, high fever and, 12 hours after infection, bleeding out of the cochlea in the inner ear. The Great Plague of London started in 1665, the year before Pepys heard the song, and continued through the year he heard it, killing an estimated 100,000 people, 20% of London's population. And the idea of laughing at seeing the corpse is a well-documented nervous reaction in an uncomfortable situation. I once heard a documentary about grief on BBC Radio 4, and recall that a man who dearly loved his wife burst out laughing when the police came to tell him she'd been killed in a road accident, something he was embarrassed by, just as Barbara Allen clearly was after the event. And isn't it common enough for people to wish they had done and said things to someone after their death, as Barbara Allen does? The ballad is called Barbara Allens Cruelty, but I suspect that title criticises the main player in the song for weaknesses and fears common to many of us.

Any thoughts?