Terra incognita : a novel of the Roman Empire

"Army doctor Gaius Petrius Ruso journeys to early second-century Britannia in the hopes of securing a quieter life, only to encounter local turbulence, a circumstance that is complicated by the vengeful plans of his slave, Tilla."@en
"Army doctor Gaius Petreius Ruso, in need of a little peace and quiet, volunteers for a posting in Britannia's deepest recesses, only to find himself involved in yet another tricky murder investigation when his slave Tilla's former lover is accused of killing a soldier--forcing Ruso to try to prove the man innocent, and the army wrong."
"In the spring of the year 118, Gaius Petreius Ruso has been stationed in the Roman-occupied province of Britannia for nearly a year. After his long and reluctant investigation of the murders of a handful of local prostitutes, Ruso needs to get away, volunteering for a posting with the army in Britannia's deepest recesses. These hinterlands are the homeland of Ruso's slave, Tilla, who has scores of her own to settle there. Her tribespeople are fomenting a rebellion against Roman control, and her former lover is implicated in the grisly murder of a soldier. Ruso is appalled to find that Tilla is still spending time with the prime suspect. Worse, he is honor-bound to try to prove the man innocent--and the army wrong--by finding another culprit."