Recycled metal fragments and small-scale bronze acquisition in northern hinterland communities of the Mongol Empire

Hinterland communities on the Mongolian plateau during the time of the Mongol Empire (13th–14th century CE) have not been extensively studied by archaeologists. Pedestrian survey and excavation in the Tarvagatai Valley of north-central Mongolia has recently located an important central place settlement known as Tsagaan Ereg, dated to the Mongol period, and having a number of pit-houses as well as evidence for local agriculture and craft production. Discovered in one pit-house was an attached metallurgical work area from which numerous pieces of slag and iron were recovered in addition to a small number of bronze pieces. Here we report on ten small bronze fragments from the Tsagaan Ereg workshop that were analyzed metallographically. These objects were made of copper-based alloys with tin serving as the primary alloying element, generally including lead as well. We review these analytical results with reference to alloy methods implemented in Mongolia and its neighboring regions over time and observe that their consistently high tin level was quite unique, suggesting that they were carefully curated and selected according to their tin content. Along with previously published metallurgical results on steelmaking activities at this same workshop, we argue for a high level of metalworking expertise within the region. Two other centers may have had contact with the Tsagaan Ereg community and these center-hinterland networks perhaps sustained the different roles and functions of these three sites.