Lindsey Davis, English historical novelist, has written most of her books in that difficult genre, the historical whodunnit.
Falco the Informer
The resourceful, bantering Marcus Didius Falco is the narrator in the Falco series, somewhat of a Sam Spade in Ancient Rome, a tough guy with an intellectual side.
Using the style of modern detective stories Davis portrays the world of the Roman Empire under Vespasian.
Flavia Albia : the next generation
This superb story of Vespasian and Antonia Caenis serves as a prelude to the Falco series, although a stand-alone and definitely not in the same style. The Course of Honour Paperback May 12, 2009
Another stand-alone novel which can be seen as a prelude, this time to the Flavia Albia series is Master and God .