The Vestal Vanishes by Rosemary Rowe

A Libertus Mystery of Roman Britain - The marriage of a former vestal virgin is always an important event, so the anticipated arrival of such a bride in Glevum is the excuse for an even more lavish banquet than usual on the Emperor's birthday feast. However, when Audelia's covered carriage finally arrives, the lady in question is nowhere to be found. Libertus investigates and makes a gruesome discovery, suggesting that Druid rebels may have been involved. But when another lady disappears, Libertus finds himself in a race against time to ensure the safety of the 'vanishing vestals'.