Technological transition and complexity reflected in bronze and brass objects from the medieval site in the Aral Sea region

The medieval period in the region near the Aral Sea must have been the era of significant sociopolitical changes and notable transitions in material culture. This prediction was tested with a metal assemblage consisting of numerous bronze and brass objects, mostly small items for personal use, excavated from the medieval (ca. 800–1000 AD) site near the Aral Sea in Kazakhstan. A technological transition driven by the growing reliance on brass was noted in the remarkable complexity in alloy recipes, in which recycled bronze and cementation brass served as the key materials along with elemental copper, tin, and lead. Different combinations of these materials were found to have resulted in the establishment of a dual technological tradition based on both bronze and brass. The notable transition and complexity as observed in the metal assemblage under consideration are interpreted as a reflection of the dynamic political settings in which both mobile pastoralist and sedentary farming groups were incorporated to form a dual social structure.