I received the following question the other day:
Does a historical fiction novel have to have a murder in the storyline?
My answer
No, not at all -– think of the historical timing as the setting. The plot can still be anything that works within the confines of that setting –- romance, family melodrama, spy thriller, mystery (without murder), or indeed murder mystery (or police procedural), or any other plotline you care to use.
Anyone got anything to add?

Or it could be speculative fiction, like Connie Willis’ Doomsday Book and To Say Nothing Of The Dog.
And here I was, trying to think of SF set in ‘real world’ history that wasn’t steam punk ie wrong era. Time travel! Absolutely classic. And to forget Connie Willis…[smacks self in face]. And of course fantasy genre can be set any time in the real world eg Mythago Wood is set at the end of WWI.