Gaugamela, named after the village it was fought by, was the decisive battle in the struggle between Alexander III and Darius II for the Persian empire. Alexander had spent two years securing his rear along the Mediterranean coast before striking inland from Syria towards the empire's heartland. This gave Darius the time to raise a new army to oppose the Macedonian king, the nucleus of which was not Greek mercenaries as at the previous battle of Issos, but the numerous heavy cavalry of the eastern Iranian provinces.
Alexander chose to take the Tigris route rather than head directly down the Euphrates towards Babylon. The Euphrates route was the more direct, but lacked foraging capacity, so the Macedonia force headed east, and crossed the Tigris before Darius' host could bar the fords. Consequently Darius was forced to look for the closest flat plain at hand in which to deploy his mounted forces for battle.
Hoping to use a force of scythed chariots to break up the Macedonian army, Darius had the plain cleared of all obstructions and levelled flat in preparation, while Alexander rested his army for several daysand fortified his camp. When he was ready to do battle, Alexander moved forwards towards Darius' position, and advanced in battle formation the next day.
Knowing he would be out-flanked on both wings, Alexander adopted a formation somewhat like a hollow square, but echeloned forwards towards the right wing. The Persians here, attempting to outflank his position, momentarily thinned their formation, and Alexander immediately charged the weak spot in the Persian line, breaking it in two which led to thee collapse of the Persian army.
Sources on the battle's progress are numerous. There are accounts by Arrian, Diodoros, Plutarch, Curtius and Justin, plus several other minor sources. Unlike the battle of Granikos however, there is no partial troop listing with number given for the Macedonian side, so some amount of conjecture is neccesary to arrive at a Macedonian order of battle.
Arrian estimates (3.12.5) Alexander's army as having 7000 horse and about 40000 foot at the battle. See my notes on Macedonian numbers and unit organisations for how the Macedonian units amongst these were organised.
In the field, the Macedonian army was divided into two halves, the left being commanded by Parmenio, the right by Alexander. Both Parmenio and Alexander appear to have controlled their cavalry more closely than their infantry, so in DBM terms we will assume that their respective phalanx brigades were 'commanded' by another subordinate general. Indeed, just as at Issos, Krateros is recorded at Gaugamela as being in command of the left wing's infantry (Arrian 2.8.4, 3.11.10), and presumably there was a similar arrangement on the right wing. This would be Koinos (Coenus), who was in charge of the right-most (ie. senior, see Arrian 1.28.3) pezetairoi unit, and was later given independant pezetairoi commands (see for example, my Gabai scenario). This will then give the Macedonians 4 tabletop generals.
The following units are mentioned (mostly in Arrian 3.11.8 to 3.12.1):
Mercenary cavalry under Menidas
The (Macedonian) prodromoi under Aretas (4 squadrons, 1.12.7 and 4.4.6)
The Paionian (prodromoi) under Ariston (given as Aretas at 3.13.3)
Half the Agrianians under Attalos
The Macedonian archers under Brison
The 'old' mercenaries under Kleander (presumably those of 2.20.5)
Alexander's Royal squadron under Kleitos
Glaukios' Companion squadron
Aristo's Companion squadron
Sopolis' Companion squadron
Herakleides' Companion squadron
Demetrios' Companion squadron
Meleager's Companion squadron
Hegelechos' "Royal" squadron
The other half of the Agrianians (presumably being those described as 'newly arrived' by Curtius at Issos)
The other half of the archers
Belakros' (Illyrian?) javelinmen
The Agema of the Hypaspists under Nicanor
The other Hypaspists (including the 'royal hypaspists', 3.13.5?)
Koinos' asthetairoi battalion (Arrian 2.22.2 for asthetairoi rather than pezetairoi)
Perdikkas' Pezetairoi battalion
Meleager's Pezetairoi battalion
Polyperchon's Pezetairoi battalion
The second phalanx line (presumably of the otherwise unmentioned Greek allies, possibly mercenaries too)
Amyntas' Pezetairoi battalion under Simmias (under Philip in both Diodoros and Curtius)
Krateros' Pezetairoi battalion
The allied cavalry under Erigyios (3 squadron's worth in Diodoros)
Parmenio's Thessalians under Philippos
The Cretan archers (Diodoros 17.57.4, omitted in Arrian's list, but they were the left wing at Issos, Arrian 2.9.3)
The Achaian mercenaries (Diodoros 17.57.4, not in Arrian's list)
Sitalkes' Thracian javelinmen
The allied cavalry under Koiranos
The Odrysian cavalry under Agathon
The mercenary cavalry under Andromachos
The Illyrians with the 2nd line (Curtius only)
Diodoros has Philotas commanding the King's "Friends" Companion squadron, meaning Hegelochos commanded a normal squadron (he gives 9 in total, and Arrian's 8 is probably in error here, see my notes for this. Of the cavalry, the Companions at 250 per squadron (except the Royal squadron, 300 strong) now numbered some 2300 at full strength, and the Macedonian prodromoi another 1000. The Thessalians were 1800 strong at the start of the campaign, and while they had no doubt taken some losses, they were reinforced by 200 men at Gordion (Arrian 1.29.4) and would therefore probably be up to full strength if not more.
Of the allied Greek cavalry, Diodoros (17.57.3) gives Erigyios' 3 squadrons as originating from Achaia and (the rest of?) the Peloponnese, Phthiolis and Malis, and Lokris and Phokis; he also says that the allies were orginally 600 strong before Granikos; Arrian mentions Beoetians (2.7.8) and 150 Eleians as reinforcements under Alkias (1.29.4). At this stage, non-Macedonian squadrons were unlikely to be organised like Macedonian ones (but, according to Curtius, soon after the battle they were so reorganised), so we cannot say a Greek ile was also a nominal 256 men as a Macedonian one was. However, assuming the 150 Eleians were part of the 'Peloponnesians' (rather than under Koiranos), this would imply an allied ile could be large as a Macedonian one.
Of the mercenaries, Menidas' command is said to be small in comparison with the 1000 Bactrians that countercharged it (Arrian 3.13.3). The 300 horsemen detailed off according to Arrian at Issos to watch the Persians on the heights were according to Curtius two squadrons' worth (using the latin 'ala'); these are unlikely to have been allies or Thessalians, since these were posted on the left wing, or Companions, who charged forwards, so were presumably mercenaries. At Gaugamela, at first glance we also have two mercenary squadrons mentioned (Menidas' and Andromachos'), but in fact it is not stated they commanded only one each (despite Brunt's tranlsation in the Arrian Loeb at 3.13.3), and there is more than a strong hint that Menidas at least commanded more, since his troops, plus Ariston's Paionians charged 'squadron after squadron' (Arrian, 3.13.4).
These Paionians almost certainly constituted just a single squadron (see my notes). Of the other Balkan cavalry, there were (together with the Paionians) 900 Thracians according to Diodoros before Granikos, presumably mostly Odrysians. Another 500 more Thracians under Asklepiodoros had arrived not long before the battle (Arrian 3.5.1).
Returning to the mercenaries, both Menidas' and Andromachos' men are stationed in front of the 'whole' of their respective rear supports. This could refer to their being very far in advance, or it could refer to them being spread out to cover a wide area. In this second case, each force would have to be comprised of more than a single squadron if it was to screen four or more other squadrons, even assuming they drew up in a shallower formation than normal.
Assuming Arrian's 7000 horse is correct, 2300 Companions, 1800 Thessalians and some 1000 Macedonian prodromoi leaves 1900 horse to be split between 1400 Thracians and Paionians and 500 allies and mercenaries. Since clearly there were more than 500 allies and mercenaries all told, either there were more than 7000 horse, or some had been left behind on unreported garrison duties, or casualties were much higher than anybody relates, even allowing for the reinforcements. I favour Arrian's figure being slightly too low for several reasons.
Firstly, no cavalry are known to have been left behind on garrison duties. This is of course a traditional infantry role - why waste expensive mobile forces on low-risk static duties? It is true that allied horse were among those left behind in Koele-Syria when Alexander marched for Egypt after Issos. This is almost certainly however the 'exception that proves the rule', for in this case, it was certain Alexander would return through the area in the future so he could pick them again and add them to the field army.
Secondly, there is no reason to think casualties had been so astonishingly high as to be greater than the known cavalry reinforcements since Granikos (at least 800 Macedonians, 200 Thessalians, 150 Eleians, 500 Thracians, and there may have been others we are not told about - this is certainly true with the infantry). While battle losses may be routinely minimized by our sources, the victorious side (as the Macedonian cavalry had always been) invariably had comparitively light casualties. Losses due to sickness and other such causes are almost impossible to quantify, but are unlikely to have numbered a thousand men - such attrition rates are only heard of in extreme circumstances (such as the worst desert or crossings), and not the mild conditions the army had so far encountered.
Thirdly, Arrian relied heavily on Ptolemy as a source for his figures. From comparisons in Plutarch and other sources, we can see Ptolemy consistently recorded rather low Macedonian troop numbers (and losses) compared to other sources.
I would estimate the Greek allies and mercenaries as being some 1500 strong - Menidas' and Andromachos' mercenary ilai, probably at least 2 each, 3 allied ilai under Erigyios, and at least another under Koiranos. Arrian records (2.20.5) one 'Menoitas' arriving with 400 Greek mercenaries, and it is usually assumed that this is a mistake for Menidas, since Menoitas is otherwise unknown, and Menidas appears for the first time after this. If these 400 mercenaries are horsemen, then they can be added to the 200 (likley mercenary) horsemen mentioned at 1.23.6.
The Macedonians at the usual 250 men per element, can be conjectured as:
Alexander's command - 49 ee
2 x Reg Kn (I) - Menidas' mercenaries
4 x Reg LH (O) - Macedonian prodromoi
1 x Irr LH (O) - Paionian prodromoi
2 x Reg Ps (S) - Attalos' Agrianians
2 x Reg Ps (O) - Brisons' Macedonian archers
16 x Reg Ax (X) - Kleander's 4000 Peloponnesian mercenaries
1 x Reg Kn (F) CinC - Alexander with Kleitos' Royal squadron
1 x Reg Kn (F) - the (new) squadron under Philotas
7 x Reg Kn (F) - the seven other Companion squadrons
2 x Reg Ps (S) - The other Agrianians
2 x Reg Ps (O) - The other archers (including the unmentioned slingers?)
2 x Irr Ps (S) - Belakros' javelinmen
12 x Reg Pk (S) - Nicanor's Hypaspists
Koinos' command - 60 ee
1 x Reg Pk (O) Sub-general - Koinos
7 x Reg Pk (O) - Koinos' phalanx
8 x Reg Pk (O) - Perdikkas' phalanx
8 x Reg Pk (O) - Meleager's phalanx
8 x Reg Pk (O) - Polyperchon's phalanx
28 x Irr Sp (I) - Allied infantry
Krateros' command - 36 ee
8 x Reg Pk (O) - the absent Amyntas' phalanx
1 x Reg Pk (O) Sub-general - Krateros
7 x Reg Pk (O) - Krateros' phalanx
4 x Irr Ax (S) - Illyrians
16 x Irr Ax (O) - Thracians
16 x Irr Bg (I) - Immobile Bg
Parmenio's command - 40 ee
3 x Reg Kn (I) - Erigyios' allied Greeks
1 x Reg Kn (F) Sub-general - Parmenio and the Pharsalians
6 x Reg Kn (F) - the other Thessalians under Philippos
2 x Reg Ps (O) - Cretan archers
4 x Reg Sp (O) - Achaian mercenaries
4 x Irr Ps (S) - Sitalkes' Thracians
1 x Reg Kn (I) - Koiranos' allied Greeks
2 x Irr LH (O) - Agathon's Odrysians
2 x Irr LH (O) - the other Thracian horse
2 x Reg Kn (I) - Andromachos' mercenaries
16 x Reg Ax (X) - other Greek mercenaries
This totals approximately 8000 horse, 40000 foot, 185 ee and 1055 AP.
The Persians are harder to quantify. From Arrian we have a fairly complete order of battle, mentioning the following (mostly from 3.8.3-6 and 3.11.3-7):
On the left wing:
The Indians bordering the Bactrians, under Bessos
Bactrians under their satrap Bessos
Sogdians also under Bessos
Arachotians under their satrap Barsantes
Indian Hillmen under Barsantes
Persian mixed foot and horse
Medes under Atropates (probably the same as the above Persians)
Kadusians marshalled with the Medes
In front of the left wing:
Sakai Scythian horse archers, under Mausaces, on armoured horses
1000 more Bactrians
100 Scythed chariots
In the centre:
Greek mercenaries under Patron the Phokian
The Kinsmen under Darius
The Persian apple-bearer footguards
More Greek mercenaries under Glaukos the Aitolian
Behind the centre:
Various Red Sea tribes under Orontobates, Ariobarzanes and Orxines
Babylonians under Bupares
Sittakenians marshalled with the Babylonians
Uxians and Susianians under Abulites
In front of the centre:
15 (?) Elephants
50 Scythed chariots
On the right wing:
Albanians and Sakesinians 'marshalled with the Medes' next to the centre
Medes (said to be to the right of the Syrians, but it seems left is meant) - possibly the 'Persian' cavalry that may have attacked the baggage with some Indian cavalry
Syrians (Koile and Mesopotamians) under Mazaios
Areians under their satrap Satibarzanes
Parthian, Hykcanian and Topeirian horse under Phrataphernes
In front of the right wing:
50 Scythed chariots
Armenians under Orontes and Mithraustes
Kappadokians under Ariakes
Arrian gives a total of 40 000 horse, and a grossly exaggerated 1 000 000 foot (3.8.6); other foot totals are also incredibly huge: Didoros gives 800 000 (17.53.3), Justin 400 000 (11.12.5) and Curtius 200 000 (4.12.13). Curtius gives a possible 45 000 horse, but Didoros (200 000) and Justin (100 000) figures as incredible as their foot numbers.
The levy foot marshalled behind the Persian line played no part in the battle, so their exact numbers are not really relevant - they will be graded Hd (O). The Persian foot guards were 1000 strong in Herodotos' time, and I shall assume they remained so at this time. After the battle, 2000 Greek mercenaries escaped with Darius along with a 'few' of these guards (Arrian, 3.16.2); clearly the mercenaries were much more numerous (they were posted against the Macedonian phalanx specifically to oppose it); as Curtius mentions 4000 escaped Issos with Darius (4.1.1-3) so would have been at least that strong, but probably no more - darius would have had diificulty recruiting more mercenaries now that Alexander after Issos. Mazaios had a few days earlier commanded 3000 horse and an unknown number of foot, including 2000 Greek mercenaries (Arrian, 3.7.1, Curtius instead gives 6000 horse), so this would fit in well with each of the two Greek mercenary contingents being 2000 strong.
Let us assume that Arrian's total of 40 000 horse is correct, and that the Persian foot totalled 100 000 including all the levy rabble (their exact numbers have little effect at 2000 men per ee). The Persians, at the usual 250 men per element (but 1000 per Horde), can then be conjectured as:
Bessos' command - 86 ee
4 x Irr Cv (S) - Mausaces' Scythians
4 x Irr Cv (O) - 1000 Bactrians
4 x Irr Exp (O) - 100 scythed chariots
1 x Reg Cv (S) Sub-general - Bessos
5 x Irr Cv (S) - Bessos' Bactrian heavy cavalry
8 x Irr Cv (O) - Bessos' other Bactrians
6 x Irr LH (O) - Parapamisadai Indians under Bessos
8 x Irr LH (F) - Bessos' native Sogdians
8 x Irr Cv (I) - other Sogdians under Bessos
8 x Irr LH (F) - Dahai
6 x Irr LH (O) - Barsantes' Arachotians
6 x Irr Ax (X) - Barsantes' Indian Hillmen
4 x Irr LH (O) - Atropates' Median horse
4 x Irr Cv (O) - Atropates' Persian or median noble horse
4 x Irr Ax (O) - Atropates' Median and Persian takabara
4 x Irr Ps (O) - Atropates' Median and Persian supporting foot archers
20 x Irr Hd (O) - Persian Susians and Kadusians
Darius' Command - 76 ee
1 x Irr El (O) - Indian Elephants
2 x Irr Exp (O) - 50 scythed chariots
8 x Reg Sp (O) - Patron's Greek mercenaries
1 x Reg Cv (O) CinC - Darius in his chariot
2 x Reg Kn (F) - Persian Kinsmen rearmed in the Macedonian fashion
4 x Reg Sp (O) - Persian apple-bearers
8 x Reg Sp (O) - Glaukos' Greek mercenaries
8 x Reg Sp (I) - Karian deportees
4 x Irr Bw (O) - Indian mercenaries
8 x Irr Bw (I) - Mardian archers
66 x Irr Hd (O) - Babylonians, Uxians, Susianians, Sittakenians and Red Sea peoples
Mazaios' Command - 98 ee
4 x Irr Ps (O) - Sakesinians
4 x Irr Ps (S) - Albanian javelinmen
4 x Irr Ps (O) - Albanian archers
16 x Irr LH (F) - Orontes' and Mithraustes' Armenians
12 x Irr LH (O) - Ariakes' Kappadokians
2 x Irr Exp (O) - 50 scythed chariots
4 x Irr Cv (I) - Indian cavalry
5 x Irr Cv (O) - Persian cavalry
1 x Reg Cv (O) Sub-general - Mazaios
6 x Irr LH (O) - Median horse
16 x Irr Cv (I) - Mazaios' Syrians and Mesopotamians
8 x Irr Cv (I) - Satibarzanes' Areians
8 x Irr LH (F) - Phrataphernes' Parthians
4 x Irr Cv (I) - Phrataphernes' Topeirians
4 x Irr Cv (O) - Phrataphernes' Hyrkanians
4 x Irr LH (F) - other Sakai
This totals 250 ee and 1241 AP.
The battle was probably fought on the last day of September, or Autumn in DBM terms. Determine the weather randomly as normal, re-rolling any result that calls for the Persians to be the invader. Determine the time of battle as normal - according to tradition, Parmenio urged Alexander to mount a night attack. As both armies had been encamped for several days resting prior to the battle, no flank marches are allowed.
The battlefied should be aligned so that the Macedonians face east and the Persians west. The only significant 'terrain' on the battlefied was the especially cleared ground in the center of the battlefield (the more lightly shaded green on the battlefield map) that the Mcedonians moved towards when edging right.
Victory and defeat:
Fight the battle until one side is broken.
To gain an overwhelmimg victory, the Macedonians must not be broken themsleves, Alexander's element must not be destroyed, and Darius' element must have been destroyed with an enemy mounted element in frontal contact with it at the time it was destroyed (in which case Darius is either captured or killed, and Alexander can mount the thrown immediately).
The Macedonians gain a decisive victory if the Macedonians are not broken themsleves, Alexander's element has not been destroyed, and the Macedonians have at least 12 mounted elements left undemoralised (the battle is decisive, and there are enough Macedonians to mount an effective pursuit so that Darius must flee Persia - the historical outcome).
The Macedonians gain a marginal victory if the Macedonians are not broken themselves and Alexander's element has not been destroyed, but have less than 12 mounted elements left undemoralised (Alexander takes Babylon, but the Persians are able regroup in Persia, meaning at least another battle before Alexander can claim the throne).
The Persians gain an overwhelming victory if they are unbroken, Darius' element is not destroyed, and they have at least 20 undemoralised mounted elements left (The Macedonians will be all but wiped out in the retreat), or, Alexander's element is destroyed while Darius' element is not destroyed and the Persians remain unbroken (Alexander is killed, his army beaten, and Darius' reign is secured).
The Persians gain a decisive victory if both Alexander's and Darius' elements are destroyed, and the Persian army is unbroken (The Macedonians are almost wiped out in the rout, but the conquered territories will not be reclaimed easily as a power struggle develops for the Persian throne).
The Persians gain a marginal victory if both Alexander's and Darius' elements are destroyed, and the Macedonians have less than 12 mounted elements left undemoralised (the leaderless Macedonian army retreats to the Mediterranean, having failed to completely eliminate the Persian army, which will soon reform under a new leader).
Any other result is a draw.
Darius had cleared the centre of the battlefield of all obstacles so that his scythed chariots woud be able to have an unimpeded field of action. To repesent the especially favouable terrain thus created, any scythed chariots within the cleared area that have a tied combat outcome, rather than be destroyed as normal, reroll their combat die roll, taking this second result in its place. This gives the chariots a slightly better chance of success, though not a huge one.
In such a large battle as this, it is not feasible to use the standard DBM PiP-dice swapping mechanism. It makes no sense to allow generals to react to events of the other side of such a huge battlefield, given no telescopes, radios, or even an organised system of aides-de-camps. It is recorded that Parmenio sent a message to Alexander saying he was in danger of being over-mastered by the Persian right wing (Arrian 3.15.1), but by the time Alexander received the meassage and responded to it, the situation had changed, and the Thesalian cavalry had gained the upper hand. Therefore generals can only swap PiP dice with other generals that are both within sight, and within 1800p.
Classing Darius and his guards as a chariot element might seem odd at first, since his was the only chariot in the contingent, but it does produce the pleasing result that Darius will recoil further from combat than an opposing Macedonian Companion element can follow-up, so giving him an historically realistic chance of escaping from combat.
The apple-bearers I have classified as Sp rather than Bw, given the hoplon-bearing figure being trampled by Darius' chariot on the Pompeii mosaic, as as (O), rather than (S), partly because he wears no helmet, and partly because there is no evidence they were particularly brilliant fighters.
I have graded some of the Greek mercenaries on the Macedonian side as hoplites. The present DBM Macedonian list grades them all as peltasts, whereas the same type of men in the Persian list are almost all hoplites. While it has been argued that Persians were more in need of heavy infantry than light, since they had more than enough lights of their own, but no quality foot, and while this seems reasonable, it must be pointed out that of course the Macedonians also had more than enough light troops of their own, just taking Thracians and what-not into account, let alone native Macedonians (the pikemen could fight as peltasts if need be, as recorded at the siege of Halikarnassos). There seems to me to be little to recommend making all Greek mercenaries serving with the Macedonians peltasts, even if the majority were. Given the position of the Achaian mercenaries in the front line at Gaugamela (Diodoros, 17.57.5), these at least are likely to have been hoplites.
The Allied and Greek mercenary horse are classified as (I). Although Allied horse could be Athenians, which are graded (O) in their own list at this date, the Athenians were only there under compulsion (like the Allied Hoplites, graded (I) since they were, to quote the rules, 'dragooned into reluctant obedience by a... ...foreign tyrant'), so I have no qualms about grading them as (I) like the others; especially since the Thessalians are mentioned by one and all as being far better than the other Greek horse, and these only rate an (O).
The notes section on Macedonian numbers and unit organisations has become so long, I have had to put them elsewhere! Follow this link...
Alexander of Macedon, P. Green, Uni.Cal.Press, 1991
Diodorus Siculus, esp. book 17 (here is the text on-line)
Plutarch's Life of Alexander
Justin 's Epitome of the Philippic History of Pompeius Trogus. Translated by J.C.Yardley, American Philological Association, Classical Resources Series, Scholars Press, Atlanta GA, 1994, ISBN 1-55540-951-2. Introduction and Notes by R.Develin.
Arrian's History of Alexander
Polyainos' Strategems and Excerpts. Translated by Peter Krentz and Everett Wheeler, Ares Publishers, 1994, ISBN 0-89005-503-3
Quintus Curtius' History of Alexander
Thanks again to Duncan Head, Michael Anastasiadis and Nik Fincher for so many useful discussions and ideas.