Romancing the Duke is the first book in Tessa Dare's new series Castles Ever After. It's clearly "historical fiction" but the exact time in history is not specified.
I enjoyed this breezy entertaining romance, but it's not what I'd call accurate historical fiction. Aside from the setting (a mouldering castle), the clothing, and the fact that the hero is a duke blinded in a duel, it's a modern romance. The heroine is quite modern, what she and the duke get up to is quite modern, and the whole subplot involving a group of people who dress up like characters in a book and travel around together felt thoroughly modern. I actually liked the subplot, I just didn't buy it in whatever time period this novel is supposed to be set in.
Romancing the Duke has many elements of a fairy tale. Recommended for anyone who enjoys historical romance with a modern heroine and who isn't too concerned about details.