Think of chemical warfare and like me you would probably think of the use of chlorine or mustard gas on the Western front during WWI, or perhaps Saddam’s murder of Kurds in Halabja at the end of the Iran-Iraq war. According to a BBC report, however, a researcher claims to have found evidence that the Persian Empire used poisonous gases on the Roman city of Dura, Eastern Syria, in the 3rd Century AD.
The theory is based on the discovery of remains of about 20 Roman soldiers found at the base of the city wall. A study shows that the Persians dug a mine underneath the wall in order to enter the city. They then ignited bitumen and sulphur crystals to produce dense poisonous gases, possibly using underground bellows or chimneys probably to help generate and distribute the fumes.
"For the Persians to kill 20 men in a space less than 2m high or wide, and about 11m long, required superhuman combat powers - or something more insidious," said Simon James of the University of Leicester "The Roman assault party was unconscious in seconds, dead in minutes. It is clear from the archaeological evidence at Dura that the Sasanian Persians were as knowledgeable in siege warfare as the Romans,"
Although the mine failed to destroy the structures, the attackers eventually conquered the city. Dura was later abandoned, and its inhabitants were slaughtered or deported to Persia.