The Ides of April by Lindsey Davis, read by Lucy Brown

The Ides of April is the birthday of Flavia Albia, a Roman informer (what we would call a detective).  She usually spends her birthday with her adopted family but this year, Flavia Albia is busy trying to find a serial killer.  Check out the first book of a new series by Lindsey Davis.368 pages. Unabridged audiobook.  11 hours.

Caveat emptor, by Ruth Downie

This is book 4 of Downie's series featuring Ruso, the Roman doctor that has a knack for solving mysteries. This time, he's stationed called out to a smaller city outside Londinium to investigate the death of a tax collector. He has more to manage than in his adventure in Medicus. This time, he's married, and his wife accompanies him on the investigation. As a bonus, the author - who is also a librarian - helpfully provides additional resources to consult, should you want to read into the factual details of the history of the area.
audio: 11 hours
text: 338 pages