The Persians used poisonous gases against the Romans in the city of Dura, east of Syria, according to an archaeologist at the Leicester University of Britain. This means they were the first to use chemical weapons. To reach this conclusion it has been based on the bodies of twenty Roman soldiers found at the foot of the city wall. Find out that the Persians dug a mine under the city wall, threw the bitumen and sulfur crystals into the hole, and. The smoke from burning these compounds was killed, according to this researcher, by numerous Romans.