Technical and economic history of western Han dynasty revealed by bronze mirrors from Zonglvcheng cemetery, Linzi, China

Abstract

In this study bronze mirrors from the Zonglvcheng cemetery in Linzi city, the unique bronze mirror production centre of the Western Han dynasty (WHD, 202 BCE-8 CE), were subjected to scientific examinations. Compositional and lead isotope ratio analyses on 41 bronze mirrors from different periods of WHD were conducted. For the first time, a mirror made of pure lead and another one made with highly radiogenic lead were identified. The compositional analysis revealed a roughly stable copper-tin-lead ratio of 14:5:1 for mirrors, providing insights into the standardised mirror production. The interpretation of isotope ratios was done by combining characteristic parameters and kernel density estimate methods, compiling a wide range of published data for comparison to mitigate the detrimental effects of the overlap effect. The results indicate that the majority of mirrors were produced within Linzi city, but their lead sources were likely from the Xiaoqinling metallogenic belt controlled by the Han Empire rather than local to Shandong province. This study demonstrates that changes in the alloy compositions and ore sources for bronze mirrors and other objects with time were influenced by state-intervention economic policies, providing a new perspective for the study of technical and economic history during the WHD.