When archaeologists first found the bones of the 19 ancient Roman soldiers and one Persian buried under the ancient Syrian city of Dura-Europos in the 1930s, they assumed they’d died in some kind of fierce underground melee—when the Persians attacked the city, they’d dug tunnels under the walls. But now, researchers believe they were actually some of the earliest victims of chemical weapons—and the first whose remains have ever been found, LiveScience reports.
Archaeologist Simon James realized the tunnels were too small for a fight, so he hit on the theory that the Persians heard the Romans digging a counter-tunnel toward them, set a fire as a trap, and threw in sulfur and bitumen to form a poison gas. “It would have almost been literally the fumes of hell coming out,” James says. He admits it's a "circumstantial case," but it's a compelling one. “I think [James] really figured out what happened,” says another historian.