The jupiter myth - Lindsey Davis

For Falco, a relaxed visit to Helena's relatives in Britain turns serious at the scene of a downtown murder. The renegade henchman of Rome's vital ally, King Togidubnus, has been stuffed head-first down a bar-room well - leading to a tricky diplomatic situation which Falco must diffuse. One murder leads to others. Londinium now has a forum and an amphitheatre; the town is a magnet for legitimate traders - and for criminals from Rome. Drinking dens are plundered by extortionists; prostitution reigns in the dark streets; the army turns a blind eye.
With his vigiles pal Petronius, Falco leads the hunt for gangsters who are intent on taking over. This will bring unwelcome encounters with faces from the past and grave threats to their present relationships. Danger and death lurk throughout their pursuit, all the way from the brand new wharves beside the River Thamesis to the familiar old haunts of organised crime back home in Italy.