George: Thank you. I hadn't had a Newf one before.

leeneia: I'd tend to agree but "Dilly" does seem much older. Your very thoughts are really why I'm tracking it more than the other versions, though.

I quote Lomax (1960, he'd upgraded his knowledge over John's in the 40's). He's referring to the great prison gospel version, "Holy Babe:"

Among the carols sung on these occasions was "The Song of the Twelve." Versions of this ancient mystic song have been recorded everywhere in Europe. Archer Taylor ("Journal of American Folklore", LXII, p. 382) suggests that its origin may be found in Sanskrit, but that all European versions are probably derived from a Hebrew chant for Passover ("Echod mi Yodea", first printed in Prague in 1526). The earliest known English translation of the Jewish religious folk song appeared in the seventeenth century, but a number of distinct forms soon developed ("The Twelve Days of Christmas," "The Dilly Song," "The Twelve Apostles," etc.

This, very casually, I admit, dates "Dilly" to seventeenth century. BTW, we know from the very reliable Norm Cohen that it appeared in the 1590 edition of the Prague Haggadah but not the 1526 one (the first printed Haggadah)