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About Alexander's Army

"Alexander inherited from his father the most perfectly organized, trained, and equipped army of ancient times."
J.F.C. Fuller, 'The Generalship of Alexander the Great'

Many books have been written about Alexander's army. This paragraph serves as a brief introduction to the subject.

Macedonian Army

Historical Background

Until the 5th century BC, before Alexander's time, Greek warfare had been a matter of amateur civilian armies on summer campaigns. Summer was the traditional season for war as it presented the opportunity to destroy the enemy's crops and grazing herds. Battles were fought by hoplites, heavily armed footmen lined up in phalanxes - opposing rows, four to eight men deep. Phalanxes would clash frontally until one side gave way. The hoplite carried a large shield, body armor, greaves, a short spear as a thrusting weapon, and a sword.

But in Alexander's 4th century BC warfare was becoming the business of specialist professional mercenaries. As Greece was a poor country, poverty drove men to the military. To hire oneself out as a soldier was just a good way to make a living. The Athenian mercenary general Iphicrates introduced light armed troops - peltasts - next to the phalanx. Peltasts were much faster than hoplites, more effective in rough terrain and they could harrass the enemy phalanx from the flanks or from the rear. The Theban general Epaminondas 'invented' battlefield tactics by concentrating his assault on one selected point of the enemy line.

King Philip II

Alexander's father, King Philip II, spent three years in Thebes from the age of fifteen (367-364 BC). This enabled him to study Epaminondas' Theban army. When Philip ascended to the throne of Macedonia in 359 BC he began to use his genius and experience to develop the brilliant Macedonian war machine. As Greek armies still consisted of both civilians and mercenaries, Philip should be credited for creating the world's first 100% professional army. In doing so, he combined the experience of the trained mercenary with the loyalty of the civilian.

While 'feudal' Asiatic armies were dominated by the mounted nobility and Greek 'democratic' armies by the infantry citizen, King Philip actually created two armies: the Royal Army of nobles and the Territorial Army of levies. This ensured a balance of power and contributed to the stability of the entire military organisation. Above that, Philip did away with seasonal campaigning once and for all. His force was a year round standing army, ready for battle in any season.

Royal Army - Companion Cavalry

Greek armies had used little or no cavalry. There was not one Greek horse at the battle of Marathon in 490 BC. When present, cavalry was used in dispersed formations for skirmishing or to pursue a routing enemy phalanx, but never as the prime weapon of assault. But the Macedonian kingdom traditionally possessed a strong nobility cavalry. What Philip did was to improve this existing Companion cavalry by drilling it to ride and attack in disciplined, dense formations for a concentrated punch. It was Philip who gave cavalry its prominent role on the battlefield.

The cavalry Companions were heavily armored horsemen armed with a thrusting spear and a sword. There were eight Companion units of 200-300 men each, one of which was the élite unit, the Royal Squadron or agema. Its task was to lead the advance on the battlefield and to protect the king when necessary. When Alexander crossed the Hellespont in 334 BC he took 1,800 Companion cavalry with him. They operated together with Alexander on the right wing during battles. Please note ancient cavalry rode without stirrups or saddles; these were not introduced before the 4th century AD.

Royal Army - Hypaspists

Without doubt the hypaspists are the most mysterious units of the Macedonian army. Historians still lack clues about what they exactly looked like and how they were armed. Adding to the controversy are the various names attached to them: Guards, Shield-Bearers and, after the invasion of India, Silver Shields (or argyraspids; their origin is equally disputed). What is certain is that the hypaspists were outstanding infantry troops who were capable of performing a wide range of tasks. During battles they served in close combat as an extension of the phalanx, protecting its right flank, and they were also well equipped for skirmishing, fast marches, storming walls and rapid advances supporting the cavalry.

Common sense indicates the hypaspists must have been, in one way or another, a flexible and mobile adaption of the original Greek hoplite. Philip had developed the hypaspists from his original body of Foot Guards. When Alexander crossed into Asia the hypaspists numbered 3,000 men divided in three divisions, one of which was the élite unit, the Royal Foot Guards or agema. This agema unit had the same role as its cavalry counterpart.

(Before the invasion of India Alexander is said to have added gold and silver to the armor of his troops; probably during this time the name Silver Shields came into being. It may have been that the hypaspists adopted this new name, or that the argyraspids were veteran units recruited from both hypaspist and phalanx battalions. What is practically for sure is that the Silver Shields were 3,000 seasoned warriors, boasting an undefeated record under Alexander. After Alexander's death they were hardly controllable: they betrayed their general Eumenes and killed their commander Antigenes by burning him alive. In the end they were dispatched to distant Arachosia where the local satrap had secret orders to wear them out.)

Territorial Army - Phalanx

King Philip transformed the original Greek phalanx into a devastating and awesome formation, the Macedonian phalanx. Because of their heavy shield, held by the left arm, the Greek hoplites had been restricted to using a relatively short spear in the right hand. Philip did away with the large shield and replaced it by a smaller shield slung over the left shoulder. This enabled the new phalanx to carry a long pike, the sarisa, now with both hands. The sarisa measured 13 up to 17 feet. Philip made the phalanx 16 rows deep; the sarisas of the first five rows were pointing forwards, producing an impregnatabe forest of armor piercing iron. The other rows lifted their sarisas at an angle upwards, forming an effective protection against missiles.

Alexander brought six phalanx battalions into Persia, each consisting of 1500 men and making a grand total of 9,000 Foot Companions, as the phalangists were called. The phalanx was well suited for a defensive role during battles - forming the center of the front and capable of stopping just any enemy attack. Because its effectiveness relied entirely on cohesion, an attacking or advancing phalanx could run into serious trouble, especially on rough or hilly ground. According to Arrian, at the battle of Issus the steep banks of the river prevented Alexander's attacking phalanx from keeping a regular and unbroken front, resulting in serious numbers of casualties. But the prime weapon of the advancing phalanx was the fear it inspired and the demoralizing effect it had on the enemy. In 168 BC the Roman commander Paullus admitted that at the sight of the Macedonian phalanx 'he was smitten at once with astonishment and terror'.

Auxiliary Troops

Heavy Cavalry - Thessalians

From Thessaly came the finest horses and horsemen of Greece and Alexander employed about 1,800 of them as allied heavy cavalry, organised in eight squadrons like the Companion cavalry. Although some sources claim the Thessalians were in fact superior to the Companions, because of political considerations they were stationed on the left wing to defend the flank of the phalanx. The Thessalian élite unit was the Pharsalus Squadron which acted as general Parmenion's personal bodyguard. The Thessalian cavalry was dismissed at Ecbatana in 330 BC although maybe up to 200 of them re-enlisted as volunteers.

Light Cavalry - Allies & Mercenaries

Accompanying Alexander's army during the invasion of Asia were approximately 1,600 light allied cavalry, hailing from Greece, Thrace and Paeonia. These units were equipped with javelins or thrusting spears and carried little or no body armor. Their main function was to protect the heavy cavalry and the phalanx from enemy attacks. In general these units lacked the exclusive discipline and training of the Thessalians and Companions. Most outstanding of the light cavalry were the 600 Thracian prodromoi or Scouts, used for reconnaissance and preliminary attacks. As Alexander was rather deficit in light cavalry during the campaign various mercenary cavalry units were added. After the campaigns in north-eastern Persia units of Sacae, Dahae, Paropamisadae and Sogdians (and Bactrians) were included.

Skirmishers - Agrians & Archers

The 1,000 Agrians (Agrianes, Agrianians) came from the mountainous north of Philip's empire and were invaluable fast and versatile crack skirmisher troops - guerillas if you like - the Ghurka's of Antiquity. Whenever an assault had to be made uphill or through hostile terrain, the Agrians were there. Alexander used them during his attacks on the Pisidians, during the encirclement of the Persian Gates and the challenging sieges of the Sogdian and Indian Rocks. Agrians wore no body armour, perhaps not even a shield.
Alexander also employed 1,000 archers, half of them Macedonian, half of them from Crete. The Cretans had a reputation for being the best bowmen of their era.

Infantry - Hoplites & Peltasts

On crossing the Hellespont Alexander had up to 7,000 allied Greek infantry, consisting of traditional Greek hoplites. Alexander apparently made relatively little use of these troops other than as reserves behind the Macedonian phalanx or as garrisons in conquered cities. From the tribal areas of Philip's Macedonian empire came about 5,000 light infantry peltasts. The traditional Thracian peltast carried a bundle of javelins and a wicker shield. Added to these troops were 5,000 mercenaries, part hoplites and part peltasts. The initial number of mercenaries was relatively low, because Alexander was virtually bankrupt at the start of his campaign. Bosworth however estimates that at the end of his reign 60,000 mercenaries were occupied throughout the empire.


King Philip had equipped his army with artillery and a siege train. The common artillery device was the oxybeles, a missile engine that could shoot deadly darts or bolts over a distance of a quarter of a mile. Alexander's battle with the Scythians at the Jaxartes river has the first recorded use of artillery in the field. The siege train included vital parts for siege ladders, battering-rams and siege towers, and many engines were built on the spot. Alexander's chief engineer was Diades who should be credited as 'the man who took Tyre'.

Persian Army

The armies of the Persian foe were made up of levies of numerous peoples, all dressed and armed according to their national custom. Thus, the Persian army can be seen as a celebration of the heterogenous harmony that - with only a few exceptions - had existed throughout the huge empire: indeed, a sort of 'United Nations peace keeping force' of Antiquity. Just as modern soldiers are willing to sacrifice their lives for abstract ideals - liberty, democracy, freedom - the original Persian soldier was also willing to die for a higher goal: his King. (Maybe one might compare this with the determination of the Japanese in World War II to fight and die for their Emperor.)

The nucleus of Darius' army were the Immortals or Apple-Bearers, the Persian élite counterpart of the Macedonian hypaspists. Traditionally they numbered 10,000 and Darius III fielded something in between 2,000 and 10,000 as his Royal Guards. Immortals carried a spear (with golden or silver apples at the butt), lavish tunics, a bow and a wicker shield. For their fighting skills the Persians hired Greek mercenary hoplites. Darius employed 10,000 of them at Issus, and these heavy infantry enemies were one of the main concerns of Alexander.

The remaining bulk of the forces were cavalry and light infantry from all corners of the empire. Prior to Issus and Gaugamela Curtius Rufus lists heavy Bactrian cavalry, Scythian mounted archers, excellent Hyrcanian cavalry, skilled Mardian archers, Barcanian horsemen armed with double-headed axes, Cossaean tribal levies, Cadusians, Cappadocians, Indians - and the list goes on and on, including "tribes unfamiliar even to their own allies". Persian cavalry was of remarkable standard; though probably not as well disciplined to attack in formation like the Companions, they outclassed Alexander's mercenary and allied horse.

At Gaugamela Darius used about 200 scythed chariots, equipped with sharp rotating spikes to demolish anything that came in their way. They were no challenge however for Alexander's mobile peltasts and Agrians. Heading the army were fifteen war elephants which could not make a lasting impression either.

Indian Army

At the battle of the Hydaspes King Porus' army, significantly smaller than its enemy, forced Alexander's Macedonians to fight their most difficult battle ever. Porus may have fielded up to 200 war elephants; they disrupted the Macedonian phalanx, claiming a toll of almost 75% in killed and wounded Foot Companions according to Diodorus.

The common Indian infantrist was the archer, armed with a huge bamboo bow as large as a man was tall. There seems to have been nothing wrong with Indian morale. Plutarch records that after some serious initial losses the Indians rallied and kept resisting the Macedonians with unsurpassable bravery. One hypothetical explanation might be that in the Hindu caste society one of the four castes were the Kshatriyas or 'Soldier Caste', which had its specific rules of conduct and behavior aimed at warfare.


Arrian - as well as Herodotus - is notorious for recording Persian armies of impossible size. Arrian quotes a Persian army of 600,000 strong at Issus and over 1,000,000 strong at Gaugamela. However, the largest army of Alexander's time that we have reliable evidence of is that of Antigonos the One-Eyed in 306 BC, counting 80,000 infantry and 8,000 cavalry. Later Roman armies never exceeded this number: about 80,000 legionaries plus 6,000 cavalry were fighting Hannibal at Cannae in 216 BC and that was reportedly the largest army Rome ever fielded. So, the figure of 80,000 seems to be a sort of natural limit to the size of these ancient armies.

The size limit has to do with the simple need to find provisions. As Herodotus writes, the land itself was the biggest enemy of the traditionally huge Persian forces. Ancient armies did not possess trucks like modern armies do, nor could they be supplied from the air. No matter how ingenious their supply system was, they basically had to live off the land. Passing armies consumed the food supply of a country like a swarm of locusts. They could never retrace their steps: they would starve when returning by the same route. Prior to the battle of Issus King Darius left his base camp at Sochi where a battle could have been fought on favorable ground. Why? It is highly feasible that after one month's stay the Persians had no choice but to move on as they were simply running out of food and water.

Ancient commanders tried to keep their armies as small as possible. Though the Persians firmly believed there was safety in numbers, this basic rule would apply to them as well as to any other nation. Smaller armies were also capable of faster marches. The Macedonians did over forty miles a day during the pursuit of Darius in 330 BC. Armies as large as Arrian records - assuming they could survive at all - would have been incredibly slow. King Darius marched from Babylon to his base camp near in Issus within three months - a distance of 1200 kilometres or 750 miles at least. This he could never have achieved with his alleged 600,000 troops, especially as he marched during the heat of mid-summer and the supply of drinking water alone would have been a sheer impossible task.

Added to the armies were the camp followers. For Alexander's army their numbers are assumed to have been one servant or slave for every cavalry man and one for every ten infantry men. In India Alexander's entire entourage is said to have included 120,000 but his standing army at the Hydaspes is still estimated to have been approximately 40,000 strong - about the same number as he started out with in 334 BC.

Some probable army sizes

  • Macedonian invasion force of 334 BC - 36,000
  • Macedonians at Issus - 30,000
  • Macedonians at Gaugamela - 47,000
  • Macedonians at the Hydaspes - 41,000
  • Persians at the Granicus - 25,000
  • Persians at Issus - 100,000
  • Persians at Gaugamela - 90,000
  • Indians at the Hydaspes - 30,000



Fear and panic were the decisive factors in an ancient battle. Now, picture yourself as a simple peltast at the battle of the Granicus or at Issus. The frontlines during these engagements were over 2,500 yards long. You might be able to see what is happening in your direct surroundings, but of what is going on one mile down the front you can not have any clue. (If you had been at the dusty plain of Gaugamela, your area of vision would have been extremely limited.) In the mêlée there are virtually no means of communications - no radios or mobile phones. Even if your own unit is doing quite alright, this does not tell you anything about progress in general. Suddenly you spot some nearby troops running for their lives... What would you do?

Ancient battles were generally over within a couple of hours. In his anabasis Xenophon records how at the battle of Cunaxa in 401 BC the entire wing of the Persian army starts routing just at the sight of the advancing Greek phalanx. Not a single blow had been delivered and the armies were still some forty yards apart. This is not Greek propaganda only - it is a genuine account of what might have happened at many ancient battle fronts. Above that, the weapons of Alexander's time were not as deadly as modern fire arms. Arrows, stones from slings and javelins could hardly pierce through armor and they were rarely lethal. In an ancient battle armies suffered death tolls around 1% or 2% and the ratings of killed and wounded combined were around 12%. The ratio between killed and wounded was 1:10 or 1:12. In the modern battles of the last centuries the number of killed averages 5% and the total of killed and wounded up to 15%. The ratio between killed and wounded is something like 1:2 or 1:3.

In Alexander's time the majority of victims fell after the battle, not during the engagement. The defeated army would run in panic, being mercilessly pursued and butchered. Even on the victors' side many horses might die from exhaustion during the pursuit. (After Gaugamela Alexander's cavalry chased the Persians for seventy miles.) Another problem for the survivors of a defeated army was that their supply system fell completely apart, their provisions being plundered by the victorious enemy. Xenophon relates how after Cunaxa the 'defeated' Greeks had to butcher their own horses for food and scavenged the deserted battlefield for firewood for cooking - arrows, shields, broken chariots, anything that could burn. The lack of appropriate medical treatment hit the victors as well as the defeated; it is unknown how many of the wounded still died afterwards or would have been permanently unfit for further service.

When all this is taken into account some records of ancient authors appear to be quite acceptable. When Diodorus and Curtius Rufus claim that during and after Gaugamela 500 Macedonians were killed against 40,000 up to maybe 90,000 Persians, though this may seem unlikely it is actually rather probable. At Issus the figures of our ancient sources indicate that over 16% of the Macedonians were killed or wounded. This is significantly higher than the average of 12%, suggesting that the Persians were certainly not the 'incompetent' army popular tradition wants us to believe. If Plutarch is correct in saying that the battle of the Hydaspes lasted for eight hours, this confirms the assumption that Macedonian morale was completely wrecked by this devastating, terrible 'Pyrrhic victory'.


agema - élite units of the hetairoi and hypaspists
argyraspids - Silver Shields; Macedonian veteran crack infantry; 3,000 strong
basilike - ile basilike: the Royal Squadron or agema of the Companions
hetairoi - Macedonian Companion cavalry; heavily armored nobilty horsemen
hipparchy - four ilai of hetairoi
hoplite - heavily armored Greek footman
hoplon - large round shield of the Greek hoplites; wooden core covered with bronze
hypaspists - Macedonian crack infantry; 3,000 strong
ile (plural: ilai) - squadron of hetairoi; 200-300 horsemen
javelin - 4 feet or 5 feet long spear; missile weapon
pelta - wicker shield of the peltasts
peltast - lightly-armed infantry man armed with a bundle of javelins and a wicker shield; Thracian origin
pezhetairoi - Foot Companions of the Macedonian phalanx; infantry carrying the sarisa and a light shield
phalanx - Greece: battle line formation of hoplites, usually 4 to 8 deep; Macedonia: battle line formation of pezhetairoi, usually 16 deep and divided in taxis
prodromoi - Thracian light cavalry; mounted scouts armed with a sarisa
sarisa - 13 feet to 17 feet pike used by the Macedonian pezhetairoi (phalanx)
sarisophori - prodromoi
taxis - Macedonian phalanx battalion of 1,526 pezhetairoi
xyston - short thrusting spear or lance of the hetairoi and Thessalian cavalry


G. Cawkwell, Introduction to the Anabasis of Xenophon, New York, 1986. Buy from

T.A. Dodge, Alexander, New York, 1996 (originally published 1890). Buy from or

J.F.C. Fuller, The Generalship of Alexander the Great, New York, 1960. Buy from or

N. Sekunda & J. Warry, Alexander the Great; His Armies and Campaigns 334-323 BC, London, 1998. Buy from or

J. Warry, Warfare in the Classical World, London, 1980. Buy from or

Written by nick

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