The Size of Achaemenid Armies

In the chapter of my dissertation on the Greek sources, I had to talk about the size of Persian armies. One of the few details about Persian armies which most Greek writers give is that they had a specific and very large number of men, and no other kind of evidence lets us estimate the size of armies in the field (the Behistun inscription lists the number of enemies killed and taken alive in various battles, and it is possible to estimate how many bow estates or temple soldiers were available in some parts of Babylonia, but neither is a reliable guide to the size of royal armies in the field). The reason why we are so determined to give the size of Achaemenid armies is that the classical tradition tells us that we should.

I side with the skeptics, such as George Cawkwell, who feel that the numbers for barbarian armies in ancient sources are not worth much, and that as they drew on similar populations and administrative systems, Achaemenid armies were probably about as big as Hellenistic and Roman ones. In a broad survey like my thesis, I had no time to propose numbers for specific cases, even if I decided that that were possible. (My master’s thesis lays out the evidence for Cunaxa as clearly as I could, although today I would add a few sentences). While arguments against vast armies are not always perfectly formed, I am not sure that the remaining believers in countless Persian hordes are really driven by the evidence (a great article by T. Cuyler Young has some suggestions about the psychology and literary forces involved). So instead of arguing back and forth about logistics and the lengths of columns, I focus on some other perspectives.

First, I talk about the nature of numbers for the size of armies in stories about battles: where they come from, how they are transmitted, and whether they hold up when compared with documents. There has been quite a lot of research in this area from an internal and literary angle, although historians do not always gather it and acknowledge its implications. Some numbers, like 120,000, show up again and again in certain contexts, and armies of hundreds of thousands or millions are always distant (they belong to foreigners, or the mighty kings of old, but not the king who is writing the inscription or the historian’s own city). However, there is also a large literature comparing numbers in narratives to documents and archives and other external tests. Specialists in the fourteenth through sixteenth centuries have been especially active in this area, but I also have some cases as late as 1943. These let us empirically test, for example, how accurately ambassadors and other influential observers could estimate the size of armies, and whether writers whose narratives impress modern researchers give numbers which match other evidence. I hope I can track down a copy of Delbrück’s Burgunderkrieg in a script that I can read and compare his conclusions about the later of his two examples to the conclusions of modern scholars.

Second, I discuss the various strategies for handling numbers in sources, such as dividing them by 2 or 10 or a hundred, ignoring them to focus on relative lengths and widths and logistical capabilities, or treating them as conventional and symbolic like some estimates for the size of demonstrations today. Studies of individual cases do not always place their chosen approach in the context of other attempts to use the same strategy, or look at strategies in general as opposed to arguments about numbers in the particular case they are studying. In my view, before we apply a strategy to a specific case where we can’t test its predictions, we should find out whether it works in cases where we can check its results against other evidence.

I hope that this approach will be helpful, and save people from spending more time asking things from their sources which those sources cannot give them. My MA thesis has a hint of my approach in this chapter, although as I reviewed it I see that some of the things I remembered writing did not make it in to the final draft. Many historians with a background in ancient history do not seem to know that n × 60 × 1,000 (LIM, the highest decimal number with a cuneiform sign), sometimes plus or minus a small number to sound ‘truthy,’ is the kind of number which specialists in the ancient Near East are very suspicious of. Many Greek numbers for eastern armies, such as the 180 myriads (the highest decimal number with a name in Greek) of soldiers which Herodotus gives Xerxes or the 170 myriads of infantry, 21 myriads of cavalry, and a myriad and 600 scythed chariots which Ctesias gives King Ninus fit this pattern.

Further Reading:

• G.L. Cawkwell, The Greek Wars: The Failure of Persia. Oxford: Oxford University Press, 2005. {the appendices contain a very clear discussion of numbers from the perspective of an Oxford classicist}
• Anne Curry, The Battle of Agincourt: A New History. Tempus: Stroud, 2005. {one historian who has compared numbers in stories with numbers in archives and does not like what she sees}
• Marco De Odorico, The Use of Numbers and Quantifications in the Assyrian Royal Inscriptions, State Archives of Assyria Studies, Volume III (Helsinki, 1995) {see especially pages 107-112}
• Catherine Rubincam, “Herodotus and his Descendants: Numbers in Ancient and Modern Narratives of Xerxes’ Campaigns,” Harvard Studies in Classical Philology Vol. 104 (2008), pp. 93-138 {disturbing example of how even scholarly translations, let alone summaries and ‘retellings,’ rework numbers in their sources}
• T. Cuyler Young Jr., “480/479 B.C.- A Persian Perspective,” Iranica Antiqua 15 (1980) pp. 214-239 {some of the arithmetic is doubtful}
• Christopher Tuplin, “Achaemenid Arithmetic: Numerical Problems in Persian History,” Topoi Supplement 1 (1997) {agrees with Young in general but criticizes his arithmetic}