Negative muons reveal the economic chaos of Rome’s AD 68/9 Civil Wars

Abstract During the AD 68/9 Civil Wars, Galba, Otho, Vitellius and then Vespasian fought for — gained control of Roman Empire. Our textual sources suggest that this was a period serious sustained disruption. However, existing analyses gold coinages produced in show only minor reduction purity coinage. Using X-ray fluorescence, we identify number heavily debased coins issued during many slightly their immediate aftermath. We confirm interior composition these totally non-destructively using muonic emission spectroscopy, thus eliminating hypothetical problems ‘surface enrichment’ or compositional differences between ‘surface’ ‘core’. Here War were indeed produced; copper used to debase time, c. 185 years earlier than first shown; regularly immediately after Wars. The metallurgical evidence from coinage now allows us Wars caused significant disruption economic system. More broadly, have shown spectroscopy is powerful tool generating important archaeological conclusions high-value cultural heritage objects simply cannot be destructively analysed, but need compositions sampled.