We can date the fall of the Persian Empire to a single day of battle on 1 October 331 BC.
It had once been the greatest empire the world had ever seen, stretching from Thrace (modern Bulgaria) in the west to the Indus Valley (in modern Pakistan) in the east, from the Caucasus Mountains in the north to the Nubian Desert in the south.
It had existed for the best part of two centuries, a strapping together of hundreds of ethnic, religious, and linguistic groups, perhaps 50 million people, under the supreme autocratic rule of a ‘Great King’, a ‘King of Kings’ – the Achaemenid Persian Emperor.
In three short years, Alexander had overrun the entire western part of that empire – Anatolia (modern Turkey), the Levant (modern Lebanon, Syria, Israel, and Jordan), and Egypt. Now the struggle was to decide whether the heartland of the empire – Mesopotamia and Persia (modern Iraq and Iran) – would also be overrun and the rule of the Achaemenid dynasty terminated.
Nothing less than this was at stake at Gaugamela (or Arbela, as it is sometimes known). Though Alexander would live and fight for another eight years – much of it to be spent in gruelling counter-insurgency operations to secure his conquests – the stakes would never again be so high. Gaugamela was Alexander’s greatest battle – the most geopolitically decisive and, as it happens, also the most tactically brilliant.
Little wonder, then, that it ranks in everyone’s top twenty. It features in Edward Creasy’s The Fifteen Decisive Battles of the World of 1851, again in J F C Fuller’s The Decisive Battles of the Western World in 1954, and in countless more-recent popular studies.
And yet we know so very little about what actually happened that day. Robin Lane Fox – whose 1973 biography of Alexander is still the best – is honest about the many problems of reconstruction. The ancient accounts are few and mainly derivative. The contemporary chroniclers were court historians imbued with the Homeric ethic of Alexander’s retinue. But even if their intention had been to record a literal truth, how could they have known it?
Battle is a chaotic collision of mass forces in which each man’s compass quickly shrinks down to what is happening immediately around him; no single man’s experience is exactly like any other’s. Memory, anyway, is defective, especially of something as traumatic as battle, with its overworked senses and surging emotions. Added to that, however, was the dust.
Gaugamela was fought on a level plain of sand and dust at a time of year when average temperatures were around 25°C and there had probably been no rain for several months. As soon as the armies began to move, and from then until the battle ended, with perhaps 150,000 men and 50,000 horses in motion, the action would have been shrouded in a vast dust cloud, reducing visibility in places to as little as a few yards.
One should view plans of the battle – including the plans we publish here – with a heavy dose of scepticism. We do not know for sure how the armies were deployed, how they manoeuvred, when and where each collision occurred, how exactly the outcome was determined. In the secondary literature, from Hellenistic times onwards, a great edifice of reconstruction has been raised, but it rests on little more than some flimsy sticks of contemporary anecdote and myth-making.
It is best, therefore, to discuss the battle in terms of broad tactical considerations. Details are likely to be wrong, and can never be certain.
The strategic challenge
Though Alexander had faced and defeated Darius himself at Issus in 333 BC, he would have known that this was not the final battle. The Persian Great King had escaped the battlefield and could be assumed to have fled eastwards deep into his heartlands. To have followed him there immediately would have been exceptionally hazardous.
For one thing, Darius had vast reserves of military manpower to call on. Greek caricatures of an ‘oriental despot’ ruling over ‘slaves’ can be dismissed. Autocratic he may have been, but none of the Great King’s soldiers were slaves, and few are likely to have been conscripts. Though raised by levies on the cities and subject peoples of the Empire, it is probable that most complements were filled by willing-enough volunteers. The cavalry, in particular, must have been first-class, for the Persians, the Medes, the Scythians, and the Bactrians were all Central Asian steppe nomads.
Another danger precluding immediate advance was the eternal military problem that the offensive loses momentum as it advances, while the defensive gets stronger. The Macedonian leader’s line of communication (back to Greece) was already a thousand miles long. He had given himself no time to consolidate his vast conquests and secure his rear. Most of the Levant and Egypt was still against him. To have plunged straight into inner Asia in 331 BC would have been the height of folly.
Thus the two-year delay – to crush all resistance in the west, to reinforce his army, to make full logistic preparation for what was to come. It gave Darius time also, but the balance of advantage must have lain with Alexander. Even so, the odds, when the great confrontation came in what is now northern Iraq, appeared forbidding.
The tactical challenge
Darius’s army probably outnumbered Alexander’s by at least two-to-one, quite possibly more, and the Persian advantage in cavalry may have been at least four-to-one.
We can probably assume that the figure given (in the Greek sources) for Alexander’s strength is reasonably accurate at 40,000 infantry and 7,000 cavalry. Most of the figures given for the Persian numbers – they go as high as a million – are ludicrous and can be ignored. But 100,000 seems possible, with perhaps 30,000 cavalry, as well as 200 scythed chariots and a contingent of elephants.
The ‘Eastern way of war’ involved mobility and shooting, epitomised by the horse-archer. The ‘Western way of war’ was almost the precise reverse: the emphasis was on the shock action of heavy infantry. Darius’s best chance lay in his potential ability to envelop the flanks of the smaller Macedonian army. He therefore offered battle on an open, level plain – one made more so by systematic clearance of any impediments to mounted movement prior to the battle.
Alexander accepted the challenge. Here was the final, decisive, world-conquering battle he had been seeking. In any case, to have refused the test of battle would have violated the Homeric ethic by which he and his peers lived, leaving him dishonoured and diminished, his right to rule in question. Gaugamela was a challenge to fight that could not be refused.
But the odds were awesome. Here is how Robin Lane Fox describes them:
The enemy’s numbers were reported to be immense… In the open plain, where no natural barriers protected his flanks, Alexander was bound to be encircled by the Great King’s cavalry, who were drawn in thousands, not only from horse-breeding areas of the Empire, from Media, Armenia, and even from Cappadocia behind his lines, but also from the tribes of the upper satrapies, Indians, Afghans, and others, some of them mounted archers, all of them born to ride, none more so than the allied Scythian nomads from the steppes beyond the Oxus.
The Macedonian army was, in fact, a combination of three distinct military traditions. The phalanx of ‘Foot Companions’ fought in the conventional Greek manner: they were close-packed heavy infantry trained for shock action. But there were refinements.
While Greek hoplites were usually a part-time militia of citizen soldiers, the Foot Companions were highly trained professional soldiers, drilled for speed and manoeuvre, and equipped with sarissa or pike, such that several ranks’ blades projected from the front of the phalanx.
Mention should also be made of the Hypaspists, around 3,000 strong, who were armed like hoplites, with spear and shield, but seemingly with lighter armour, making them an elite of mobile shock infantry.
The open plains of northern Greece (Macedonia and Thessaly) were represented by the mounted Companions, the heavy shock cavalry that both Philip and Alexander employed as their masse de manoeuvre and instrument of rupture or Schwerpunkt.
The hill tribes of the wilder parts of the Macedonian Empire in the southern Balkans provided light infantry, like the Agrianian javelin-men, who, under Alexander, became a kind of elite special-forces unit.
The Macedonian army at Gaugamela was a modern combined-arms force of professional veteran soldiers, with the emphasis on complex manoeuvre and shock action – the attritional shock of the phalanx, the lightning shock of the cavalry, with the Hypaspists often providing the hinge between the two.
How should it be employed to minimise Darius’s advantage in numbers, mobility, and shooting-power, and to maximise its own advantage in hitting-power?
It seems there were four distinct elements to Alexander’s solution to the tactical problem posed by Gaugamela: an oblique approach; an echeloned formation; refused flanks; and strong reserves. This combination had the effect of turning the entire Macedonian army into a huge, mobile, flexible, hollow square.
The main strength was on the right. Here the bulk of the Companion cavalry was deployed. This, remember, was the key strike-force, its role to spearhead the break-in to the enemy line at the moment of decision, this to be determined by the leader himself, who would ride at the head of the cavalry wedge.
Left of the cavalry, in the centre of the Macedonian line and forming its anchor, were the great blocks of the pike phalanx, but echeloned back from right to left. This ‘refusal’ of the left-centre was designed to delay the action here until the stronger Macedonian right had broken through.
Both outer flanks were also ‘refused’ – that is, angled backwards – in anticipation that the numerically superior Persian cavalry would overlap them both and threaten either to roll up the Macedonian line or break into the rear and surround the entire army. In the case of the weaker left flank, this was, then, a double ‘refusal’, in that the Macedonian line was both echeloned back and, at the far end, bent back.
This was the deployment of the Macedonian elements of the army, but Alexander used his second-rate elements – Greek, barbarian, and other auxiliary units, perhaps as many as 20,000 in total – to form a second line behind the first. Their task was to plug gaps in the main line, to reinforce the flanks if threatened, to extend the flanks if necessary, or even to form a rear face, turning the entire army into square, in the event of complete envelopment.
In short, almost the whole of Alexander’s plan was a defensive response to Persian numbers and mobility; he was prepared to fight a ‘cauldron battle’ if necessary. But the secure defensive can be the essential springboard for the successful offensive. So it was at Gaugamela.
This was the meaning of the oblique approach to the Persian line. The Macedonian advance involved a rightwards shuffle, reducing the risk of envelopment on the right flank while pushing forward the mounted strike-force and positioning it for an attack somewhere on the left-centre of the enemy line.
Information about Alexander’s deployment of his troops, and the intention implicit in it, is more reliable than information about the action itself – for all the reasons explained above. Some oft-repeated statements about the action are quite ludicrous. I will give one example.
We are invited to believe that Darius launched his scythed chariots in a frontal attack on the phalanx, and that the Macedonians opened their lines to create lanes through which the chariots passed, only to be dispatched by the reserve forces behind.
Chariots are even less capable of breaking solid infantry than cavalry. To have used them in this way would have been madness. Equally, the most-effective defence against such a chariot attack would have been to halt, close ranks, and present a hedge of projecting blades to the oncoming horses.
What seems possible is that we have a garbled report of an abortive chariot attack in which many vehicles ended up passing around pike ‘hedgehogs’, much as Ney’s cavalry flowed around Wellington’s infantry squares at Waterloo. But we do not know, and the nonsensical accounts of this incident fossilised in the sources merely underline the exceptional difficulty we have, at this distance, in understanding what actually happened in the battle.
What follows, however, is an attempt to identify the essentials. The Persians attacked on both flanks, mainly with cavalry, but supported by infantry. Their enemy’s oblique advance and refused right flank forced them to swing wide in an attempt to find the end of the line and achieve an envelopment. This had the effect of stretching the Persian line.
The Persian attack on the opposite flank was harder still, for here, remember, there was a double refusal – an echeloned line and a bent-back end. This had the effect of stretching the Persian line to an even greater degree than on the opposite flank, thereby weakening the impetus of its attacks and making effective envelopment exceptionally difficult.
The crisis of the battle
The discipline and solidity of Alexander’s heavy formations was critical: the Foot Companions, the Hypaspists, and the Greek hoplites were especially adept at dogged defensive fighting, their formations effectively impenetrable as long as morale held. This remained true even with limited breaches in the Macedonian line.
The fighting on the Macedonian left is reported to have become exceptionally desperate, and the sources also record one major breakthrough in the centre, by a large Persian cavalry force that ended up in the far rear looting Alexander’s baggage-train.
This is not difficult to explain. An oblique advance by an army of 47,000 men must have been a challenge for even the most highly drilled soldiers, even without the need to respond to enemy attacks. Add in the dust, the chaos, the confusion, and it would have been astonishing if gaps had not opened in parts of the Macedonian line.
But the character of Alexander’s infantry – again, much like the British infantry at Waterloo – was such that it could endure for a time even with a ruptured line by fighting in defensive islands. For a time: but not indefinitely. Everything depended on the Schwerpunkt on the right.
At some point, Alexander judged the moment had come to launch the Companion cavalry against the left-centre of the Persian line. He may have detected a gap, caused by the stretching effect of his own angled formation. He may have sensed the drain of Persian strength away to the flanks. This may, indeed, have been the very core of his tactical conception.
Knowing that Darius was bound to launch a fight for the flanks, he had so arranged things that this became a mechanism for leaching power from the enemy centre. His deliberate intention was perhaps to extend and prolong the fight on the flanks to the point where a potential breaking-point appeared in the middle of the enemy line, close to where the Great King himself held station.
The charge of the Companions pierced the Persian line and penetrated deeply, sending shock-waves left and right, and immediately endangering the Great King, who promptly fled. The Macedonian cavalry were followed by the Hypaspists and the Foot Companions, who now crashed into a faltering line. Panic spread through the Persian centre and much of it began to disintegrate.
The story – the Homeric version concocted by Alexander’s courtiers – is that the Macedonian king would have run Darius down but for Philip’s old general Parmenion on the left, who made a desperate appeal for help.
This is another transparent falsehood: Alexander’s job was to complete the victory over the Persian army, and that required the Companion cavalry to continue the action until all sections of the enemy line had been broken and were in flight.
Oddly, the court panegyric has the effect of diminishing the achievement. Alexander may have worn the mask of Achilles and exercised what John Keegan called ‘heroic leadership’, but he was a master tactician.
‘The whole art of war’, wrote Napoleon, ‘consists in a well-reasoned and circumspect defensive followed by a rapid and audacious attack.’ Moreover, as Clausewitz, who theorised the generalship of Napoleon, explained, a basic principle of strategy is ‘to concentrate force at the point where the decisive blows are to be struck, for success at this point will compensate for all defeats at secondary points’.
Gaugamela was a practical application of such ideas, and more: a defensive designed to draw and fix the enemy’s forces, so as to weaken him at the point already selected for the decisive blow. It stands with just a handful of other great battles as an enduring tactical masterpiece.
Robin Lane Fox (1973) Alexander the Great (Allen Lane).
John Keegan (1988) The Mask of Command (Penguin).