Sasanian Chemical Warfare?

A scientific re-assessment


Sasanian Chemical Warfare?
by Khodadad Rezakhani

Khodadad Rezakhani (Dept. of History, University of California, Los Angeles) co-authored this commentary with Reza Yeganehshakib (Dept. of History, University of California, Irvine) 

A recent piece of news regarding the history of Iran  ["University of Leicester archaeologist uncovers evidence of ancient chemical warfare"] surprised those of us involved in the study of history. Usually, when Iran/Persia gets mentioned, it is either in the form of nuclear “threat” currently providing fodder for news networks or in the shape of ghouls and monsters who get massacred in hundreds by a few brave and freedom loving Greeks, making puddles of blood in service of human rights and freedom.

So, it was interesting to see that the only time the Persian history makes it to the main news (BBC: "Ancient Persians 'gassed Romans'") is still in connection with violence, particularly “gruesome” tactics against the beloved, civilised, freedom loving Romans who just killed their enemies by boring them to death, apparently.

To give it some background, the Sasanian Empire of Iran/Persia was founded by Ardashir I in 224 CE and it soon came to include not only Iran but also Iraq and parts of the Caucasus and Central Asia. It quickly expanded eastwards to the northern parts of India as well, replacing the Kushan Empire. In the west, it was met with the colonial power of Rome whose expansionist policies had taken it far from the Italian peninsula and into the Near East, the neighbourhood of the Sasanians and the domain of their political ancestors, the Achaemenids. From early on, the Sasanians and the Romans were involved in border skirmishes which never were decisively concluded in either side’s favour.

However, in the middle of the third century, Shapur I, the son of the founder of the dynasty, succeeded in defeating and killing one Roman emperor (Gordianus III), defeating and imprisoning another one (Valerian, who died in Iran) and forcing yet another one to sign a humiliating treaty (Philip the Arab). So, at the time that the supposed “chemical warfare” in question was taking place, the Sasanians had the definite upper hand in the war with the Romans. This is again interesting, since comments such as “the Sasanian Persians were as knowledgeable in siege warfare as the Romans” (quite common when there is talk of ancient history) somehow imply that the Romans were the Americans of the ancient world, the most civilised, knowledgeable, and technologically advanced of all ancient peoples to whose exalted positions all others needed to aspire, despite constant reminders from those such as the Chinese that this could not be farther from the truth.

Regardless of whether there is any political meaning behind the news of the Persian use of chemical warfare and the current controversy regarding “weapons of mass destruction”, it is still interesting to see whether this new piece of research has any scientific value. For this, we turned to a colleague, Mr. Reza Yeganehshakib, who is a PhD student at the department of history, University of California, Irvine. Mr. Yeganehshakib comes to UCI with previous degrees in Chemical Engineering (BS) and Environmental Studies (MS). He has a strong understanding of the scientific processes that might have resulted in what has been reported in the news bit above. The following are his comments.

The Roman soldiers that were found could have been killed because of the lack of oxygen due to the blockage of the mouth of the tunnel, or possibly because of the collapse of the earth and the blockage of the mouth of the tunnel behind them. The dimensions of the tunnel, as described, must be precisely analyzed and compared to the material and texture of the soil and its mechanical properties to see if the Roman reinforcement and structures could resist the weight of the mass of the soil above it or not.

Roman and Persian miners would have needed some means of providing light in order to be able to see what they were doing. The sulphur crystal and bitumen, mentioned in the article, are among the chemicals that were commonly used in order to produce torch light at the time. The presence of these chemicals and burning them could surely produce hazardous gasses. Gasses like Carbon Monoxide (produced as a result of the lack of enough oxygen required for the complete combustion in the tunnel), sulphur oxides, and unburned Hydrocarbons are among the most lethal gasses produced by burning these chemicals to produce enough light.

The accumulation of these gasses in either side of the tunnel was surely quite deadly. The accumulation of the harmful gasses could have been caused either by the physical blockage of the entrance or mouth of the tunnel or due to the air pressure difference between the inside of the tunnel and the outside air pressure particularly at the mouth of it. If the outside air pressure was higher than that of the inside, then the gases inside could not be released to the outside and would accumulate there. The elevation difference of the tunnel and its entrance is a crucial factor, as the air density and pressure in the higher altitudes is lower than that of lower altitude.

If the Persian tunnel, as shown at the first image, was built at a lower elevation and had an open entrance to enter the air, then a hole or any other open area could have unexpectedly connected the Roman and Persian tunnels together. the air and the harmful gases, either produced by those chemicals to produce light or intentionally to produce harmful gasses, would have suddenly rose up and gotten into the Roman tunnel due to the air pressure difference. Therefore almost all of the gasses that had lower densities than air would have rose up to the Roman tunnel. At the time if the Roman tunnel mouth was closed for any reason, even if the process of the gas transfer from Persian side to the Roman side was slowed, the gasses already existing in the Roman tunnel would have remained for awhile.

All the burning processes need enough oxygen, fuel, and temperature. The latter can be produced by the initial ignition that Sulphur Crystals might have cause; however, the gases produced as the result of combustion are proportionate to the amount of fuel and air. By finding evidence of the existence of the quantity and quality of the fuel (a very difficult task), we can determine the amount of the gas released by creating a mass-energy balance for the chemical reaction of this combustion to see if enough hazardous gases were produced in order to kill 21 soldiers (20 Romans and one Persian). We also need to see if there as enough oxygen or air to realize the combustion is another issue.

So, these scientific take on the news imply that although the intentional use of “chemical weapons” was possible, the case could also have been a simple case of accumulation of poisonous gasses as the result of the burning of the chemicals used for creating light in the tunnels. In the former case, one should celebrate that the Persians were indeed as “advanced” as the Romans in their knowledge of warfare tactics and technologies. If the latter, one would also wonder the wisdom of trampling the history of Iran/Persia in all other occasions only to give it credence when violence is involved.



more from Khodadad Rezakhani

b b gi

by Iran parast (not verified) on

They want leve us to be but Iran will be for ever down with bbc and there musalman poppets.


Thanks for your appreciation

by Shantanu Chatterjee (not verified) on

As I said victors write their history,the core west i.e US,UK,France,Germany were overwhelmingly uncivilized during antiquity but reading the western viewpoint you would think that their direct ancestors were roaming around in Athens when they were in all probability wearing animal skins and eating raw meat.

The Greeks always showed a far far higher respect to the east Persia,India,China,Egypt etc in their writings than the supposed 'descendants' of Greek culture who were deemed unsuitable even for slavery and best avoided.

Khodadad Rezakhani

India, China, and Iran

by Khodadad Rezakhani on

Your comments were the most sensible and enlightening of all, and I am truly thankful for the fact that you seem to have given it some thought, although the rest of the successors of ancient Iranian culture here seem to have only cared about passing gas.

 You are right, and again right about China and India's returning "prestige", even if grudgingly as you mentioned. But notice that this is following the "normalisation" of both Indian and Chinese political stance in the world, and their rising economic importance. Iran, sadly, is still far behind in this sense and there are too many obstacles on its way to achieve this normalisation.


Victors write history

by Shantanu Chatterjee (not verified) on

Its pretty simple actually the West over the past 3-4 centuries 'won' in the sense it is now far ahead of the east which was culturally and scientifically far superior than the west throughout much of the rest of human history.

So now we are told the Greeks invented everything and the three principle eastern civilizations India,China,Persia did very little when the fact is the world's first democracy was Indian (vaishali),the first giver of human rights was Persian(Cyrus) and the first meritocracy based administration was Chinese(the mandrin bureaucracy).But apparently we eastern folk did nothing except give a lot of 'talk about spitituality and stuff'(India),Killed many people(Persia) and tortured many more(China).

Though in the case of China and India it is slowly changing as we are slowly regaining our place in the world,so now the fact that chinese invented(Gunpowder paper etc) Indians invented(decimal number system etc) are being acknowledged however grudgingly.

Ari Siletz

Makes you blow a fuse!

by Ari Siletz on

"In some of the strikes in Gaza it's pretty clear that phosphorus was used," Peter Herby [a Red Cross coordinator]told The Associated Press on January 15 2009. "But it's not very unusual to use phosphorus to create smoke or illuminate a target. We have no evidence to suggest it's being used in any other way."

Yet, a 2000 year old archeological site contains proof that Iranians used chemical weapons? They should send a few English archeologists to Gaza; they seem to run circles around the Red Cross when it comes to finding the evidence.


Migozeem, Mimireem, Sazesh nemi pazireem!!!

by SALTY on

Good job Sasanians, We are this ( Ma Ineem) :-)


BBC are paid to do Gooz Tactic for centureis

by Rooh e Mosadeq (not verified) on

Here is a good example of BBC fairness and independence! They go and find any Majnoon who talk and do research against Persians and then they make a big headline out of it for the rest of the world!!!!

Film 300,Persian Vs Arabian Gulf, The wrestler film, Phosphorous gas and hundred other propagandas against Persians are all part "Global GooZ Tactic"
in order to demonising a culture and a nation....

Irooni Aghah Bash

Darigh ast Iran Ke viran shavad...


BBC said persians used phospourous

by king david (not verified) on

thats an amazing coindcident !

because phospourous used extensively by isreal same time BBC posted this



by Immortal Guard! (not verified) on

But if they lighted it then it was going to explode in their faces!


Persians with gas masks

by Aref-Adib on

So this photo of the ancient Persians with gas masks is photoshoped?



Anonymous Observer

Superb Job

by Anonymous Observer on

Thank you Khodadad Jan.  I have a very limited knowledge of Chemistry, but the first thought that went through my mind when I read the BBC piece was whether or not the gasses were the byproducts of chemicals burnt to create light.  Your detailed analysis confirmed my suspecion. 

And your point about the western assumption that Rome was superior in all aspects is quite right.  And it is even more relevant when you mention the Chinese, who were way ahead of the Europeans in many aspects of technology, even maritime technology and ship building. 

I am sure that you have read Guns, Germs and Steel.  If you haven't, please do and you will see how advanced the Chinese were in comparison with the Europeans.    



عالی گفتی

امیر کبیر (not verified)

عالی گفتی. در واقع از هر فرصتی این انگلیسها استفاده میکنند تا ایران را خراب و بدنام کنند.

یکی نیست به اینها توی شهر لایچستر بگوید خودتون یادتون رفته در زمانی که بابای خمینی را از هند به ایران فرستادید معجزه جدیدی را اختراع کردید و آن اینکه آخوندهای نوکر انگلیس بالای منبر معجزه میکردند. در شهرهائی مانند شیراز و غیره مردم را در مسجد جمع میکردند و بعد از نوحه خوانی ناگهان از زیر منبر سینی های کباب کوبیده و تافتان و ریحان بیرون میامد و این سینی های پی در پی کباب آنقدر از زیر منبر بیرون میامدند تا همه غذا بخورند. و این بود معجزه آخوندهای پیرو انگلیس. در واقع تونلی زیر منبر حفر شده بود که تا آشپزخانه ادامه داشت و از آنجا سینی های کباب به زیر منبر فرستاده میشد.

حالا بنده نمیخواهم روده درازی کنم و افشاگری نمایم که در دهه هشتاد مارگارت تاچر خودش یکپا بمب شیمیائی بود، و از اطاق خوابش یک حلبچه ساخته بود.

اکنون هم که این مطلب را مینویسم دو طرف صفحه اول ایرانین.دات.کام پر است از تبلیغات برای برنامه های فارسی بی.بی.سی. منظور آنکه ما هرکاری بکنیم ریشمان پیششان گروست و راه چپ و راست را بسته اند.