The units of Alexander the Greats` army

Alexander had inherited one of the most powerful armies of the ancient world from his father. His father, Phillip II of Macedon had transformed Macedonia from an insignificant member to the dominant power in Greece by transforming the army.

But what units made up the army of Alexander the Great?

The army of Alexander the Great consisted of the Hetairoi, the Pezhetairoi, the Hypaspists as well as of additional contingents of Hoplites and Mercenaries.

Let`s find out more!

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The units of Alexander the Greats` army

The army of Alexander the Great consisted of the Hetairoi, the Pezhetairoi, the Hypaspists as well as of additional contingents of Hoplites and Mercenaries. According to ancient sources Alexander commanded 32,000 to 48,000 men.

That was the army that had originally been built by his father that would enable Alexander to conquer the Persian empire and live a life that would later earn him the nickname „the Great“.

Are you also interested in the life of Alexander the Great? Then you might want to check out the biography of Alexander that was written by the ancient Roman writer Plutarch (and that is still one of the most important sources for our knowledge about Alexander). You can find a translated version here* on amazon.

Let`s take a closer look:

The Hetairoi

The Hetairoi were the so-called companion cavalry, a unit recruited of the sons of Macedonian noblemen and in battle directly commanded by Alexander.

The word hetairoi as the term for those elite cavalrymen is quite interesting and gives an insight into the relationship between king and soldiers.

The Kingship in Macedonia was not only based on the royal bloodline. A huge part of the macedonian kings` legitimation originated in his capability as a military leader. The close bond between king and army is clarified by calling the soldiers companions of the king.

The Hetairoi were recruited from the landowning nobility of central Macedonia. Due to the width of central Macedonia horses had always played a bigger role than in other greek states.

But it wasn`t until Philipp II of Macedonia that the cavalry was molded into a battle-deciding force.

They were usually wearing armor and a helmet. The primary weapon of the Hetairoi was a double-headed lance, the so-called xyston. If one head would break off during battle the cavalryman would turn the lance and use the second head or he would drop the lance and reach for his sword.

When Alexander attacked the persian empire in 334 BC he had approximately 1800 Hetairoi with him. One year later another 300 would reinforce his cavalry.

The hetairoi were probably the first shock cavalry of the ancient world. The squadrons would usually be led by Alexander himself and were positioned on the right wing of the battle formation.

The macedonian phalangites did not have the speed and maneuverability for a decisive attack. Their main purpose was to pin down the hostile infantry and to provoke gaps in its formation.

The Hetairois`charge would usually decide the battle by taking advantage of these gaps in the hostile infantry formation. They would not be used against intact and well-organized infantry formations! Source.

The Pezhetairoi

Pezhetairoi has the word hetairoi in it. „Pez“ can be translated with „by foot“. So the pezhetairoi were the royal companions by foot.

Once again, calling the soldiers the kings` companions by foot shows the closeness between the king and his soldiers that was typical for the macedonian kingship!

The Pezhetairoi are probably Philipps II masterpiece. The origins of the pezhetairoi lie in the typical militias of the classical greek era. Here you can find my article with more information on the Hoplites & the requierements for being a Hoplite.

During the classical greek era, the soldiers of the greek city-states (sparta as the exception, click here to read my article on the surprisingly rigid social structure of sparta) were farmers and craftsmen who were called upon arms during the summer.

Since these soldiers had to be home in spring for sowing and in fall for the harvest the time in which war could be waged was limited.

That was where Philipp II (Alexanders father) saw his advantage. He had spent three years of his childhood as a hostage in Thebes. At that time Thebes was the dominant military power in Greece and Philipp learned a lot about the use and the shortcomings of the phalanx.

You can find out more about how the greek phalanx worked and why it was so effective in my article here.

When Philipp II became king he decided to improve the phalanx to make it an even better fighting force:

He increased the reputation of the phalanx by calling them royal companions by foot (as already mentioned).

Philipp II also provided every recruit with a plot of land that was large enough to provide his livelihood. But that plot of land would not be farmed by the soldier, the so-called phalangite. He would live close to the macedonian capital where he would focus on his military training.

That daily training resulted in well-trained and highly disciplined men who were able to maneuver in strict formations.

Another change was that the macedonian phalanx was organized differently than a traditional greek phalanx. More on how the phalanx worked in my article here.

The macedonian phalanx was also armored differently. While greek hoplites would often wear bronze cuirasses or a more cost-efficient cuirass made out of glued layers of linen (even the type that was made out of linen would offer pretty good protection) macedonian phalangites would only wear light body armor.

They would also carry a much smaller shield than their greek counterparts. The hoplon, the shield of the traditional greek hoplite, had a diameter of 31-39 inches and weight 18 pounds.

Because of the weight, the hand of the shield-bearer would grab a handle at the edge of the shield and a leather fastening at the center of the shield connected the forearm to the shield.

The reason why the macedonian phalangites had to carry a much smaller and lighter shield was their primary weapon. The pezhetairoi used the sarissa, an 18 ft long and 14 pounds heavy double-pointed pike.

Due to the weight of the sarissa (around 14 pounds), it had to be used with both hands. The main advantage of the sarissa was a longer reach. The average greek hoplite was equipped with an 8-14 ft long spear. The longer spear gave the macedonian phalangite a crucial advantage over other greek hoplites.

But since two hands were needed to use the sarissa there was no hand left to wield a large shield. The shields that were used by the pezhetairoi had a diameter of 24 inches and weighed only about 12 pounds. They were usually carried with a belt around the neck.

One downside of the smaller shield was that it offered a lot less protection! What sounds like a major flaw is actually quite smart when you look at the enemies the units of pezhetairoi were designed to encounter.

Philipp II of Macedon created the pezheairoi to establish his dominance over Greece.

The greek states that he had to defeat to reach that goal all relied on the traditional hoplite phalanx. Please read my article on how the greek phalanx worked to find out more.

These traditional phalanxes relied on much shorter spears than the macedonian phalangites so sacrificing protection to gain a longer reach made sense.

Especially since the danger of getting hit with arrows was quite low. Greeks during that time did not really use bows and arrows for war. They saw the use of that weapon as cowardly and would prefer to face the enemy face to face instead of shooting arrows at him.

So Philipp II of Macedon and his soldiers didn`t really have to worry about arrows.

That changed with Alexanders’ invasion of the Persian Empire. In contrary to the greeks the Persians heavily relied on archers.

But the positive sides of the phalangites equipment still outweighed the negative sides.

The macedonian phalangites carried approximately 10 pounds less equipment than a greek hoplite making them much faster.

Philipp had also reduced the number of personal belongings that could be carried on the campaign.

The idea behind that was to reduce weight and increase the marching speed. And indeed, the macedonian army could move around at a much greater speed than other greek armies.

The pezhetairoi would usually form the center of the macedonian battle formation. Their vulnerable right wing would usually be covered by the hypaspists.

The already mentioned hetairoi would be offensively positioned at the right wing. The left wing would be manned by cavalry from allied Thessaly (used defensively) and other groups like mercenaries. More on those groups later.

It is important to note that neither Philipp nor his son Alexander saw the Pezhetairoi as the force that would decide the battle.

The phalanx was not expected to kill a lot of enemies, it was expected to keep the hostile infantry busy until a gap would emerge. That gap would then be exploited by the Hetairoi.

Since Alexander would usually command the offensively used Hetairoi the infantry would be commanded by one of Alexanders’ senior officers. Usually by his most reliable general Parmenion.

The Hypaspists

The Hypaspists were basically armored like the greek hoplites with the exception that not all of them wore a cuirass.

Technically Hypaspists would also be included in the concept of pezheairoi (royal companions by foot).

But since their equipment and their use during battle was extremely different from the already mentioned pezhetairoi phalangites I wanted to present them as a separate unit.

The big shield, the hoplon, and the around 6.5 ft long spear made the Hypaspists ideal for special tasks.

Alexander the great would usually position the Hypaspists on the right side of his battle formation as a connection between the pezhetairoi and the Hetairo cavalry.

Since the pezhetairoi had to use both hands to operate their sarissa the right wing of the macedonian phalanx was extremely vulnerable since the long sarissas (up to 22 ft.) made it almost impossible for the phalangites to turn quickly. So especially the right flank was always a popular target for a hostile counterattack.

Protecting the right end of the pezhetairoi phalanx was the Hypaspists` task!

During Alexanders` campaign into the persian Empire, the Hypaspists began to adapt the fighting style of the traditional greek hoplites. Check out my article to find out more on how the traditional greek phalanx worked.

The men who were recruited into the Hypaspists had about the same background as the Pezhetairoi. They were usually sons of Farmers and craftsmen. But the Hypspists were specially selected for physical strength and above-average loyalty.

The reason for that lies in the origins of the Hypaspists as Guard Infantry.

They were even closer to the macedonian kings than the pezhetairoi (but not as close as the Hetairoi). If the king would fight by foot, for example during a siege, then the best Hypspists would also function as a royal bodyguards.

After Alexanders’ campaign into India (more on if Alexander really marched into (modern-day) India here in my Article), the Hypaspists would also function as a palace guard for the royal palaces in Susa, Ecbatana, and Babylon.

By the way, there was also a unit of elephants that was dedicated to protect the royal palace in Babylon. More on if Alexander ever used these elephants in battles here in my article.

After Alexanders’ death the Hypaspists would also escort his funeral procession.

There were probably 3000 Hypaspists in Alexander the greats army.

To highlight their elite status the most capable Hypaspists carried shields with silver fittings. In 328 BC, during the preparations for Alexanders` campaign into India, the shields of the Hypaspists got silver fittings which resulted in their new name argyraspids (silver shields).

If you want to learn more about Alexanders’ Indian campaign and if he really got as far as India you might want to check out my article here.

The Hoplites

Alexander the Greats` army also included contingents of hoplites. Now that might sound a little odd since the Hypaspists were basically armored and fighting like hoplites.

It is important to know that Alexander, just like his father, was the leader of the League of Corinth. The League of Corinth was extremely important in Alexanders’ justification of his invasion into the Persian empire.

The members of the league of Corinth were obliged to provide the hegemon (Leader= of the league) with warriors.

The Hoplites that were sent by their hometowns to aid Alexander remained with him until he dismissed them in 330 BC after he claimed that the campaigns` goal, revenge, had been accomplished.

The total amount of allied greek hoplites was around 7000 men strong. They were led by a macedonian officer. The strategic value of these greek allies was rather low, they would mostly be used as a reserve.

There are debates among historians that their main purpose might have been to ensure the well behavior of their hometowns. That the greek hoplites from the League of Corinth were basically hostages inside the much larger macedonian army.

The Mercenaries

The last group of soldiers who fought for Alexander were mercenaries.

At the beginning of the invasion into the persian empire, there were about 5000 mercenaries. But with the duration of the campaign, the number of mercenaries increased.

Many of them switched directly from persian to macedonian service.

In 324 BC Alexander banned the recruiting of mercenaries because he feared that his provincial governors could use mercenaries to overthrow him.

Ironically most of the dismissed mercenaries would be recruited by the Athenians for a rebellion against Alexanders’ governor in Macedonia.

But that is a story for another time.

How big was the army of Alexander the Great?

The number of men that served in Alexanders’ army vary depending on the source. Most sources claim that Alexander commanded between 32.000 and 48.000 men.

The composition changed with time. But I will try to give a rough number for the year 334 BC when Alexander started his invasion of the persian empire:

Hetairoi1.800 men
Pezhetairoi10.000 men
Hypaspists3.000 men
Allied cavalry3.200 men
Allied hoplites7.000 men
Allied infantry & Archers (from the Balkans)8.000 men (7.000 infantry & 1.000 Archers)
Mercenaries5.000 men
Additional expedition corps that had been operating in western Asia minor since 336 BC10.000 infantrymen, commanded by Parmenion.
Size of the army of Alexander the Great in 334 BC

I hope you enjoyed our trip into the time of Alexander the Great. If you are interested in the unusual methods Alexander used to secure his reign over the persian Empire you can check out my articles here and here.

The types of units that Alexander had used were actually also used by his sucessors. And when the Romans came in contact with Macedonia they as well had to face these units. More on that here.

Take care of yourself because you deserve it. You really do.

Until next time

Yours truly

Luke Reitzer


S. English: Army of Alexander the Great (2009).

L. Burckhardt: Militärgeschichte der Antike (München 2008).