Today the UK Guardian has repeated the Canard about Ring-a-O'Roses being about the black death, which has been thoroughly trashed in this thread.

They also gave a few other 'histories' of Nursery Rhymes. Is there any more foundation in any of these?

Jack and Jill - refers to King Louis XVI and Marie Antoinette.

Mary Mary Quite Contrary - About Mary I, "Bloody Mary"

Three Blind Mice - Also Bloody Mary, but this time noblemen convicted of plotting against her.

Little Miss Muffet - "Patience Muffet, apparently, was a real girl. Her stepfather was an entomologist, who, during the late 16th century, wrote the first scientific catalogue of British insects." (See this site, which thinks not)