Ring O' roses is indeed about the black death. Goosey goosey gander is about the puritan represion of priests under the later tudors (and again under Cromwell), Humpty Dumpty refers to the failed attempt to take Gloucester from Parliamentary forces using a pontoon bridge during the civil war (1643), (the king is therefore charles 1). Nursery rhymes are often historical allegory or oral history. (miss muffet existed, by the way). (as did dr foster. The grand old duke of York was an expeditionary force to the netherlands during (I think, could be wrong) the anglo dutch wars (nutmeg wars), Little Jack Horner was Sir John Horner, who allegedly pilfered the deeds to the village of mells from Henry viii by reaching into a dispatch case (the pie). Mells was the "plum". Theres been a lot of argument (mainly by the Horner family) about wether he was given it fair and square or not.....
Thats all I can think of a the mo....