Observations on the production techniques of Roman period fibulae from the upper Oder basin in the light of microscopic analyses

The article presents the results of microscopic research of fibulae from the Roman period, discovered in the upper Odra river basin (currently southwestern Poland), in the territory of Przeworsk culture. The artifacts chosen for the research are well preserved and easily identifiable chronologically. The aim of the research was to determine three fundamental groups of traces: remains of the fibula production process, traces of their usage and possible signs of their repair process. In order to perform the observation, a DinoLite digital microscope was used, with 20–300× magnification. While there are numerous works about the finds from other cultural areas (primally from the area of Wielbark culture, Elbe Germanic people), the publications about the artifacts of Przeworsk culture are usually focused solely on their classification or typology. Issues related to the production process or usage of fibulae are hardly ever addressed, or appear only as an appendage to other matters. The obstacle to a precise examination of the fibulae was the damage inflicted on them during the post-depositional process, and occasionally occurring thermal damage (in the case of fibulae from cemetery sites, most likely caused by the cremation process). Sometimes, however, the observation was hindered by damage caused by corrosion, especially in the places of contact of two parts of a fibula, made of different metals. Despite this, it was possible to see traces of the techniques used for production of the examined artifacts with the help of different tools, together with traces of usage of particular parts of the fibulae. For example, the tools used for the production were identified, such as files, pincers or hammers.