Geochemical and Pb isotopic constraints on the provenance of the Lupa Capitolina bronze statue

Abstract

Newly reanalyzed samples from the bronze statue of the Lupa Capitolina have provided lead isotope and trace element data. The lead isotope results coincide with those previously reported in the literature, but are approximately 20 times more precise. The high-resolution lead isotope analyses and the compositional data, especially lead concentrations higher than those found in copper ores, clearly reveal a mixing trend during the casting process. The addition of lead as a flux makes the lead isotopic composition unsuitable for determining the provenance of the bronze. However, comparisons with available data on bronze artifacts from the same epoch as the Lupa Capitolina statue (11th–12th centuries AD) support evidence of the monopolistic copper trade during the early Frankish and later Germanic imperial periods. Furthermore, element zoning in the Lupa Capitolina highlights details of successive melting within the metallurgical chaîne opératoire. Lead and other trace metals may have become enriched at the statue’s surface due to slow cooling after casting.