A ‘Roman Brass’ Age: a transformation in copper-alloy composition in Estonia and northern Latvia during the Roman Iron Age, identified by pXRF

Brass quickly overtook bronze as the dominant copper alloy across vast areas of the Roman world and beyond during the 1st century BC. It has also been established that the quality of this brass changed over time. To establish whether a rapid transition from bronze to brass also took place in the north-eastern Baltic, over 1200 copper-alloy objects were analysed non-destructively by pXRF. They were primarily sourced from the tarand cemeteries of Estonia and northern Latvia, which date to the Pre-Roman and Roman Iron Ages. The aim was to establish which alloys were in use during these periods, then to determine whether any chronological trends were visible and, if so, for which typological groups. The results show that there was a major shift from bronze to brass towards the end of the Pre-Roman and the early Roman Iron Ages. This is followed by a decline in the use of brass in favour of gunmetal over the following centuries. The results also suggest the existence of an introductory period when traditional bronze and newly arriving brass items circulated together. However, this period better matches a time slightly earlier than that traditionally proposed for the start of Estonia’s Roman Iron Age. This pXRF survey presents a better understanding of the arrival of brass in the north-eastern Baltic and adds to our knowledge about the effectiveness of long distance trade and communication networks that transferred new objects, ideas, and technologies to these distant communities.