Dear Jansy,

The wonderful John Sutherland (British, but last I heard lecturing here in Pasadena at Cal Tech) in a lecture on Wuthering Heights says that setting novels back 30 or 40 years from the date of publication became a commonplace called "antedating" in mid-Victorian literature. He gives as examples, Wuthering Heights, Jane Eyre and Vanity Fair.

Mansfield Park of course is pre-Victorian so may have started a trend. Be that as it may, I have found a web page which addresses your concerns in some depth ("a Calendar for Manfield Park") and here is its URL:

http://www.jimandellen.org/austen/mp.calendar.html

I hope to tackle the Cinderella question myself - have located the book by folklorist Marian Roalfe Cox (1892). Some day anyway.

Carolyn