Because the arcs and tropes fall into similar patterns, authors will often "change things up" by placing the couple and/or detectives in a new setting. Ellis Peters, of course, created a triumph with Cadfael. She not only captured the time period, she knew the history exceedingly well and could smoothly work it into the mysteries.
There's also Jeri Westerson's King's Fool Mysteries series, in which the real life court fool, William Sommers, investigates a crime for each of King Henry VIII's wives (Williams Sommers did, in fact, survive them all, including Queen Mary and Elizabeth I). The series captures Tudor England perfectly.
Likewise, Georgette Heyer produced some of the best contemporary romances of Regency England, in part due to her research of the time period.
F
elicia Grossman's books are unique since they take place in the Jewish East End in the early 1800s.The only snag with unique settings in romance is that often the books feel more like world fantasy--that is, the books concentrate more on all the stuff the protagonists are dealing with than their actual relationship. With something like the manga series Barbarities, I don't mind since the setting of Renaissance Europe is so entirely fun. But not all Heyers' books interest me equally and even Grossman's fascinating milieu couldn't hold my interest.
The best solution appears to be to present the milieu so seamlessly, the reader doesn't realize how much is being communicated. KJ Charles's Band Sinister comes to mind. Charles tackles the issue of individual do-you-own-thing behavior versus for-the-social-good behavior versus for-survival-in-society behavior. Maintaining the tensions between these positions is possible because Charles plays fair with the time period: it is what it is.
