The wooden shield has rotted and no image remains, but fragments of paint could be detected, says Christian-Heinrich Wunderlich, the head of the restoration workshop at the Landesmuseum in Halle. Under a microscope, the pigments were identified as "Egyptian blue", which was widely used in the Roman Empire, and vermilion, which was only available in a few Mediterranean locations at that time. "These pigments were not cheap and must have been Roman imports," Wunderlich says. Examinations under the microscope revealed that the paints were applied in layers, and that the wood was prepared with a chalk and lime base to...