The Population of the Achaemenid Empire
When I wrote my MA, I spent months wracking my brains and scouring libraries in hopes that I could estimate the population of the Achaemenid empire within a factor of two or three. Little did I know that a much more precise figure was available!
By share of population, the largest empire was the Achaemenid Empire, better known as the Persian Empire, which accounted for approximately 49.4 million of the world’s 112.4 million people in around 480 BC – an astonishing 44%. Originating in modern-day Iran, the empire was first established by Cyrus the Great and included parts of Central Asia, the Mediterranean, North Africa, and even European territories such as ancient Thrace and Macedonia.
Guinness Book of World Records, “Largest Empire, by Percentage of World Population,” accessed September 2014 http://www.guinnessworldrecords.com/records-9000/largest-empire-by-percentage-of-world-population
While I hope that everyone who remembers their high-school science classes is smiling (do they really think they know whether the world population was closer to 112.4 million than 112.3 million or 112.5 million?) this is a real problem. However you define “the population of the Achaemenid empire” that population was a number, and shaped the lives of everyone who lived within the empire. Many people venture to estimate the population in writing without giving a basis for their calculation, while many cautious estimates deal with earlier or later periods or only cover part of the empire. For myself, I would be satisfied if I knew the population of the empire within an order of magnitude (eg. “tens of millions” or “30 to 300 million”), and I won’t repeat a figure unless I can show how it was estimated or at least from whom it was cribbed. This one was cribbed from Wikipedia, and I think that tracing it further would be futile.
Edit 2015-10-04: Specifically, back in September 2011 the Wikipedia page “List of largest empires” gave a population of 49.4 million in 480 BCE with no source for that particular number given. The version of September 2011 estimated that this was 20% of the population of the world, citing a book by Barry Strauss which indeed estimates that Xerxes ruled 20 million of the 100 people living in the world in 480 BCE, but does not cite a single source for either number; by September 2013 this estimate of the world population in 480 BCE had been ‘improved’ to 112.4 million and attributed to an Encyclopaedia Iranica article on Darius the Great which says nothing whatsoever about the population of the world. By the same date the estimate of the population of the empire in 480 BCE had been rounded to 50 million, a guess which commonly appears in books.
Further Reading: My MA thesis discusses research on the population of the Achaemenid empire. A writer at Nature http://www.nature.com/news/2011/111019/full/478300a.html assumed a 1% margin of error in world population estimates, the Indian Government decided that their 1951 census missed at least 1% of the population (source) and Gerhard Heilig of the UN estimates that their world population figures have a margin of error of 1-2% (source). No census data for any significant part of the Achaemenid empire survives, and in many regions archaeologists have not even tried to count the remains of villages and measure the area of towns to allow some sort of systematic estimate.
Edit 2021-12-05: fixed links broken when WordPress introduced the block editor, converted to block editor
Edit 2023-06-09: I am not sure where Bret Devereaux got his estimate of 25 million people in the Achaemenid empire (“c. 25m, very roughly”), that is higher than McEvedy and Jones’ 17 million in 400 BCE and lower than Aperghis’ 30-35 million in 350 BCE. He has not had time to reply to my question, but perhaps he averaged the McEvedy-Jones and Aperghis estimates. In my view Aperghis used more evidence and better methods so his numbers should be taken much more seriously although that does not mean that they are correct. There is a recent overview of the evidence in Josef Wiesehöfer, “Demography and Demoscopy,” in Bruno Jacobs and Robert Rollinger (eds.), A Companion to the Achaemenid Persian Empire (Wiley-Blackwell: Hoboken, NJ, 2021), pp. 27-38
Given the political aspect of Persian history for Iran, I would consider any Iranian source to be worse than an order of magnitude-error guess somebody was calculating right in front of me.
Achemenid population estimates aside, It seems likely to be that the population estimate for the world population in 500 BC is a pretty dubious lowball as well – the 100 million originally given and sourced (most probably to McEvedy and Jones) was a very lackadaisical guess that was pretty much straight-up a series of exponential growth curves with only the loosest justifications. More modern estimates tend to much higher, generally at least 200 million – estimates of American, African, and Southeast Asian populations have greatly increased since they made their guess 40 years ago. And then there’s India, which is the, ahem, elephant in the room. Modern lowball estimates give a population of at least 50 million just in the Indian subcontinent alone.
Suffice to say they underestimated every population that wasn’t either a) Western history or b) China, which had a census
I am surprised to see people using the numbers in McEvedy and Jones after I had a look at the book! As I said in my MA thesis, they expect people to believe that in 400 BCE four times as many people were living in the territory of modern Greece as the territory of modern Iraq, and that just smells wrong. And of course because they =assume= exponential growth, economists should not cite them as evidence that the world population has undergone slow exponential growth for a long time.
I agree that South and Southeast Asia are big problems, since they clearly had big populations, but did not leave many archives and census figures.
I did, in fact, basically split the difference between McEvedy and Jones on one hand and Aperghis on the other. An ugly solution, but I didn’t want to get stuck debating the question which (as far as I know, and of course I am not the Achaemenid expert here!) remains deeply uncertain.
I agree that Aperghis’ estimate is far better researched; McEvedy and Jones’ figures are…well, they’re often quite bad, but many of Aperghis’ numbers strike me as a touch high, thus my emphasis on *very* roughly there and tendency to want to aim for the bottom of his range (or just below it).
Ok, I just wondered because the number was not one of the ones I was familiar with and I could not recall a big estimate since I finished my MA. I have not read the new article by Wiesehöfer closely yet, but his main point seems to be that work on documents and survey archaeology from Iraq might help narrow down an estimate there like Lin Foxhall, the Polis Project, and Ian Morris have done for the Greek world.
And I saw hits to this post coming from some corporate social media site so I decided to update it.
Regarding your last post and the stiffness of twined linen, see the post dated 10 October 2021 here https://www.romanarmytalk.com/rat/showthread.php?tid=31507 (image backed up here). I have a photo of a patch of quilted linen standing vertical in my Mouseion article, earlier vision in a 2016 post.