Miss Moppet is hosting The Royal Mistress Challenge, in which one has to read books, fiction and non-fiction, based on royal mistress that actually have existed. There are a number of examples of various mistresses from a number of eras and countries. You can find the link to the challenge to post here.
As for me, I plan to read these books:
• A rose for the crown
• The Other Boleyn Girl
• The Last Boleyn