^
Barbara Hambly,
Search the Seven Hills via the link above. Although it's filed under the fantasy imprint, it's actually a perfectly mundane and very good murder mystery set in ancient Rome during 2nd century CE, and has a good period-accurate historical flavour to it (Hambly has degrees in history and now teaches the subject at a local college). It's one of my personal favourites and I've always wished that she'd been able to sell a series out of it (or entertained the notion of a sequel as one of her “Further Adventures” novelettes).
There was definitely also another Roman historical mystery by a popular author in the listings yesterday, but I can't seem to find it again, and unfortunately I seem to have conflated my Roman historical sleuth writer names, since the one I guessed at wasn't it. ETA 2: It's
Inquest by Stephen Dando-Collins (
Wikipedia), a respected historian. I haven't read it, but this was on my Fictionwise wishlist back in the day, when it was an e-Reads title before ORM acquired them.
ETA: also, Barbara Parker has a freebie. I
read her 1st-in-series Suspicion of Innocence when it was an e-Reads Read an Ebook Week giveaway several years ago and quite liked it, enough that I'd recommend trying whatever else she had out for free.
And Loren D. Estleman has some freebies. ISTR liking his Sherlock Holmes pastiches.
And the Reid Bennett mysteries by Ted Wood, set in small-town Ontario, are decent if dated in a rather retro-80s sort of way, and another thing I
read as an RAEBW giveaway.