Amid all the uproar over chemical weapons in Syria comes this surprising revelation: What could be the earliest archaeological evidence of chemical weapons was uncovered in the country—and it is some 1,700 years old. A mixture of sulfur and pitch combined with fire was the first way humans gassed their enemies, explains Discovery News. It dredges up 2009 findings by British archaeologist Simon James, who asserts that such a poison gas was used during a siege on the Roman-controlled city of Dura-Europos around AD 256. The site was excavated throughout the 20th century, first in 1920; in the next decade, the bodies of 20 armor-clad Roman soldiers were found in one of the counter-mines they dug in order to access the tunnels made by the invading Sasanian Persians.
The original theory was that the collapse of the tunnel killed them. But James offered proof that the Romans were actually gassed: A jar near the bodies contained residue composed of pitch and yellow sulfur crystals. National Geographic shares James' explanation: "I think the Sasanians placed braziers and bellows in their gallery, and when the Romans broke through, added the chemicals and pumped choking clouds into the Roman tunnel." Death would have come within minutes. There is one bit of archaeology that could predate it: a sulfur and pitch fireball that struck Alexander’s army in 327 BC. But a Stanford research scholar notes that there's no way to determine whether it was purposefully or accidentally ignited. (More on this history front: Researchers now say ancient Egypt sprang up faster than we thought.)