Almost 2,000 years ago, 19 Roman soldiers rushed into a cramped underground tunnel, prepared to defend the Roman-held Syrian city of Dura-Europos from an army of Persians digging to undermine the city's mudbrick walls. But instead of Persian soldiers, the Romans met with a wall of noxious black smoke that turned to acid in their lungs. Their crystal-pommeled swords were no match for this weapon; the Romans choked and died in moments, many with their last pay of coins still slung in purses on their belts.
These 20 men, who died in A.D. 256, may be the first victims of chemical warfare to leave any archeological evidence of their passing, according to a new investigation. The case is a cold one, with little physical evidence left behind beyond drawings and archaeological excavation notes from the 1930s. But a new analysis of those materials published in January in the American Journal of Archaeology finds that the soldiers likely did not die by the sword as the original excavator believed. Instead, they were gassed.