I Know Something You Don't Know! [Melody of kids' teasing songs]

My point, which you didn’t seem to pick up, is that the chant was sung on the exact same pitch pretty much everywhere. The shape of the melody would, of course, be the same no matter what note it started on. The “song” is known by everyone, and it’s sung the same way. But what’s intriguing is that it’s sung on just about the same pitch everywhere.

How is the date when this rhyme first appeared in print evidence that it is not, in fact, much older? Clearly its transmission has been, and still is, through the oral tradition, amongst children. Were many people writing down kids’ rhymes before the late 19th century? I doubt it. There may be no way of proving it is older, but there is no evidence that is not. (And there is the evidence of tradition, not to mention of its actual content, that it is.)

Also, how have you got “three out of four experts” agreeing here? Everyone else mentioned is simply relying upon the authority of The Oxford Dictionary of Nursery Rhymes. That is one source, quoted uncritically by others.

Thank you for fighting my ignorance.

Well, that is food for thought.

Read the Snopes entry. The same patterned rhyming with the same opening line was published multiple times in a five year period, but never before that. Given that background, why is the “ashes, ashes” version considered the “correct” one and where is the evidence that it refers to the plague? As Snopes further notes, the plague occurred before Chaucer wrote anything, (actually between the time he was four and seven). This means that for the “plague” version to be the “real” one, the kids would have looked into the future and chosen nineteenth century words with nineteenth century pronunciations (to make the rhyme and meter work) in the middle of the fourteenth century. Have you seen Chaucer? His English was very different.

As to people writing down children’s rhymes, why do you doubt that it happened? Old King Cole was written down (in at least one version) in 1708. The big surge in publishing children’s rhymes began with Mother Goose in 1765, although several books preceded that. Many children’s rhymes were recorded much earlier than 1881.

Now, could there have been a children’s rhyme with the same meter 530 years earlier? Sure. But to have that same rhyme refer to the plague in fourteenth century English, changing just enough to update the language without changing the meaning (and carrying forward that meaning for 530 years without anyone happening to take note of it?), not plausible, at all.
And then there is the point that the first reference to the plague shows up 80 years after one specific version is printed.

If you want to go fight with Cecil, have at it, but that rhyme was not contemporaneous with the plague.