A Re-evaluation of the Debasement of the Roman Silver Coinage as Presented in David Richard Walker’s Metrology of the Roman Silver Coinage

Abstract

David Richard Walker’s Metrology of the Roman Silver Coinage analyzed the silver content of over 5000 Roman denarii, antoniniani, and drachmae using x-ray fluorescence (XRF) spectrometry. His results have been widely cited and used by scholars in the fields of Roman economic theory and numismatics. This thesis seeks to prove that Walker’s XRF results were not only inaccurate, but inconsistently so. Corrosion and surface enrichment on silver-copper coins have caused surface-level elemental examinations, like XRF, to produce incorrect results. The results from Walker’s XRF analysis have been compared against results from four individual wet chemical studies. The comparisons display striking, and significant, differences. I am forced to conclude that Walker’s data does not in any way align with the true silver content of the coins he analyzed. As a result, this thesis will re-examine several theories and hypotheses posed by scholars who used Walker’s data and propose new, more appropriate, uses for Walker and XRF analysis outside of the examination of corroded silver-copper coins.