Not only did his manner of death remove the normal place to put the coins necessary for the ferryman to ferry his soul to the land of the dead -- and this was cause for concern since everyone agreed that his ghost would be especially nasty -- but it created panic among the slaves. Since each slave had a reason to wish the master dead none of them was above suspicion, and since the entire slave body could be executed should any of them be found guilty of murder, individual slaves tried to cut deals with Marcus, the area's imperial representative.
Marcus is smart enough to know that he needs Libertus, a Celtic freedman and mosaic maker, to help him solve the mystery of the murder. Libertus had recently laid a mosaic floor at the house of Crassus in a new library that had been created for Crassus' brother, Lucius. Since Crassus had no interest in reading, the scrolls were dull, the room lighting abysmal, and the room was being used not as a library at all, but as a holding tank for wayward or suspected slaves.
Libertus has a slave of his own, Junius, whose treatment stands in sharp contrast with the treatment of slaves in the Germanicus household. Junius is treated as an apprentice in the mosaic-laying trade and is to Libertus almost what Libertus is to Marcus. The library mosaic had been Junius' masterpiece.
When Marcus orders Libertus to accompany him to Crassus' estate, Junius is left behind, but he is summoned to the estate when Libertus is knocked out, mid-investigation by person or persons unknown. Unasked, Junius tastes his master's food when it is revealed that a competent herbalist had been teaching her techniques to one of the female slaves ministering to the recuperating Libertus.
The clues in The Germanicus Mosaic are well laid out so solution to the mystery is possible, but it is not so obvious that you can't miss it. It is a good story since Rosemary Rowe writes delightful historical mysteries.
