See list of Genres.

Those that pertain to take part within unmodified history, but leave such big questions as to current evidence that they obviously don't. (In most Lovecraft the evidence is hidden and/or obscured and so there is little or no proof that they didn't happen, okay the people didn't exist, but on that account we wouldn't be reading historical, we would be reading history.) Or things which are based on history, but obviously modified history.

Examples

Randel Garetts Lord Darcy Novels (Sherlock Holmes in an age of magic.)

Ars Magica
Space 1889 (Okay this ones a dodgy call, see Steampunk)