The Battle of Guagamela: Re-Assessing the Military Factors and Numbers

Jason Poirier Lavoie Essays

“I should be glad, Onesicritus, to come back to life for a little while after my death to discover how men read these present events then. If now they praise and welcome them do not be surprised; they think, every one of them, that this is a fine bait to catch my goodwill.”1

– Alexander “The Great” III of Macedon


Gaugamela was the final battle of an epic war. The Macedonians had led an invasion force down the eastern Mediterranean, liberating the Greek city-states of Asia-Minor and conquering “by the spear” everything that lay in their path. The vast and mighty Persian Empire, of whom they were taking territories, was not able to stop their southward march and when the Macedonians were greeted as liberators in Egypt, there was only one direction for them to turn: towards the Persian heartland. The Macedonian-Greeks invaded with Homeric vigour and with the idea that they could disseminate their superior Greek culture to the ends of the earth. However, before they could accomplish this they would have to defeat the Persian army in a decisive battle; Gaugamela was that battle. For the Persians, it was the axial event in which their ancient cultural dynasties finally fell to foreign conquerors and it dawned a long era of foreign imperialism. For the Macedonian-Greeks it confirmed their superiority and made them masters of half the (known) world. The ramifications of Gaugamela are profound; in brief, it was pivotal in the ascent of modern civilization. Gaugamela can, therefore, be regarded as one of the most important battles in history and this essay sets out to uncover the military strategies that were employed there.

There is very little literature on the military strategies used at Gaugamela, although there are many military histories. Most historical accounts are more concerned with establishing what happened rather than why and how it was possible. Historians generally tend to glorify Alexander “the Great” the Third of Macedon (henceforth Alexander) as an unmatchable strategist, a veritable God of War, without considering the real military factors that determined his success. This essay will treat Alexander as a commander-in-chief (hegemon) and a first-class general, but foremost as a man. A leader who was governed by the realities of war as much as any other. This may seem an obvious distinction but it is important to be mindful that Alexander was deified just prior to Gaugamela and for those who recorded it, he was not simply a man.

Gaugamela was actually the second confrontation between the great Persian King of Kings Darius the Third (henceforth Darius) and Alexander. The other battle had been a narrow victory for Alexander at Issus two years prior, but Gaugamela was by far the more decisive battle and as so it will be the concentration of this essay.

Ancient sources recount that Darius stood with an army of more than a million men, while Alexander (for whom the data is more reliable) defeated him with only 47,000 soldiers.2 This seems highly improbable and likely the result of the propaganda that was intended to glorify Alexander and the battle. This essay will engage ancient and modern sources to give a more accurate estimate of the number of soldiers who fought for the Persians in the battle of Gaugamela. It will also discuss several peripheral military factors that affected the outcome.

The greatest challenge in this endeavour is to separate the legend of Gaugamela from its reality. To do this we shall commence with a critical analysis of the primary and secondary sources to provide an informational foundation from which the rest of the essay will be built upon. The second section is a detailed account of the march to Gaugamela from both Darius’ and Alexander’s perspective. It explains the preparations and key events in the days before the battle. This section will demonstrate the many peripheral factors, like morale and reconnaissance, which contributed to Alexander’s success and Darius’ failure.  Section three deals with the battle itself. This is where I will present my hypothesis on how many Persian soldiers actually fought at Gaugamela. In addition, I will offer a series of insights into Alexander command strategy. Finally, there will be a brief epilogue to discuss the questions that are aroused by the essay.


  1. Peter Green, Alexander of Macedon, 356-313 BC: A Historical Biography (Berkeley: University of California Press, 1991)
  2. P. A. Brunt, trans., Arrian’s History of Alexander and Indica (Boston: Harvard University Press, 1976), 510