The querns from the Roman military camp at Hermeskeil (Rhineland-Palatinate): Bridging the gap to Caesar’s De Bello Gallico

The late-Republican military camp at Hermeskeil (Rhineland-Palatinate) is one of the few known archaeological sites from the Gallic Wars and can be linked directly to the historical record given in Caesar’s De Bello Gallico. Among the numerous finds are fragments of several badly preserved querns whose provenances can provide valuable information regarding the dating of the camp. The Hermeskeil querns are made from an unusual variety of rock types compared to material from contemporary settlements in the region. In order to determine the provenances, modal mineralogy, whole rock geochemical compositions as well as mineral chemical compositions were analysed on all fragments found until 2017. Besides vesicular lavas, the querns were made of sedimentary rocks, pebble-rich carbonates and arkoses, as well as acidic lava and plutonic rock. One volcanic rock fragment of a legionary quern is produced from lavas from Cap d’Agde in southern France. Several other querns of the Late La Tène type have their origin in Mayen in the Eifel. The plutonic rock is vaugnerite, a rare rock of granodioritic composition, which can be traced via the oppidum of Bibracte to quarries in the northern Morvan. The rhyolite comes from La Salle in eastern France. Except from the querns made of vesicular lava from the Eifel, none of these materials are known from any contemporary archaeological site in the Hunsrück area. What is more, all of them were discovered far away from their regular areas of distribution. Therefore, these querns directly reflect military supply structures as well as troop movements, because during Caesar’s campaigns damaged pieces had to be replaced by locally available products. In a time when the Roman military could not yet rely on a well-functioning supply-infrastructure this category of finds bears the potential to provide important information in connecting the Hermeskeil site with written sources. It becomes possible to prove a use of the camp during Caesar’s campaign in 51 BCE, because it was not before 52 BCE that the Roman army had moved within the distribution area of all the querns represented in Hermeskeil. Provenance studies are therefore a valuable supplement for our fragmentary picture of the Gallic War, which to date is almost completely based on historical sources.