"Biblical" bronze coins: New insights into their timing and attribution using copper and lead isotopes

Ancient Judaean bronze coins are important for reconstructing the timing of events, for their cultural information, and for understanding alliances in the Eastern Mediterranean as Roman influence replaced the Hellenic Empires. Isotopic analyses of metals important in archaeology have become increasingly routine using multiple collector-inductively coupled plasma-mass spectrometry. A relatively nondestructive acid swab method for the isotopic analysis of lead (Pb) and copper (Cu) in bronze is described and tested for various isotopic sampling biases. The method is used to examine changes over time in fiduciary metal sources in the Levant during the first centuries bce and ce. The metal sources, timing, and attribution of Judaean "widow's mites" (ca. 80-40 bce) and the bronze coins of Roman governors Valerius Gratus and Pontius Pilate under Tiberius (14-37 ce) are used to illustrate how changes in the isotopes of Pb (widow's mites) and Cu (Roman governors) can be used to elucidate the compositional chronology of archaeological bronzes from this region and period.