Alexander the Great’s army

The Macedonian cavalry

The army of Alexander the Great could be called Macedonian because it fought for the Macedonian king. Its troops were like many other armies in Antiquity only partly recruited from the kingdom itself. These soldiers from Macedonia proper were supplemented by considerable forces from other territories. The native Macedonians however remained the most important part of the army. These men served both in the cavalry as well as in the infantry. The most prestigious of the mounted troops were the hetairoi or companions. The companion cavalry had its origins in the retainers kept by the Macedonian royal house. At first the members of this elite unit were recruited among the Macedonian nobility. During the reign of king Philippus II its strength had however been raised from approximately 600 horsemen to over 3000 troopers. Only part of these were selected among Macedonian nobles, others were recruited from Thessaly and other parts of the Greek world. These hetairoi were organised in ilai or ‘wings’ of some 200 men except for the basilikè ilè or agèma, the royal squadron, which had a strength of 300 to 400 cavalrymen. In battle these units of Macedonian hetairoi were generally formed up in a wedge formation.

The companion cavalry was equipped with metal helmets and various types of body armour. Some troopers wore linen or leather corselets reinforced with metal scales while others equipped themselves with bronze or iron breastplates. A number of horsemen may even have spurned the use of armour, either for reason of comfort or out of sheer bravado. Shields were probably only reserved for dismounted actions. The hetairoi usually carried a variety of heavy thrusting spears to act as heavy shock cavalry, though they were on occasion armed with javelins. A sword was at all times in use as a secondary weapon. These could be of the hoplite type as well as a curved slashing variety.

Heavy cavalry was very effective against opponents with low morale, but it could do little of consequence when confronted with a determined enemy in good order. Horses are by nature prone to flee any danger, though they can be trained to charge straight at a mass of people at great expense of time and effort. Considering the low resistance of equines to hardships it is however difficult to assess to what extent the Macedonian heavy cavalry could be provided with well-trained warhorses. On prolonged campaigns it is very likely many horsemen had to make do with whatever mounts were available.

In addition to the shock troopers of the hetairoi a small number of light cavalrymen designated prodromoi or scouts were part of the native Macedonian cavalry. These horsemen were usually equipped with javelins when employed on reconnaissance missions, but armed with a cavalry version of the sarissa they served as heavy cavalry sarissophoroi in battle. Normally these Macedonians operated closely with the light Paeonian, Illyrian and Thracian cavalry. Confusingly these mounted Thracians were also known as prodromoi.

The Macedonian infantry

Beside the cavalry mentioned above there were also infantry units that were recruited in Macedonia. Amongst these the most important were the pezhetairoi or foot companions, of which some were also given the mysterious title of asthetairoi. These pezhetairoi were recruited according to a territorial system in which the various provinces of Macedonia each provided a single taxis or regiment. To reduce the threat of a rebellion at home the army assembled for the Asian campaign was predominantly made up of regiments from the seditious northern districts. Command of the foot companion regiments was usually entrusted to nobles originating from the same area as the men themselves. The various taxeis often carried the name of their commander. Modern studies often assume that each of the foot companion regiments had a strength of some 1500 soldiers, but it is not unlikely that in fact the units as a result of dissimilar losses and replacements had varying numerical strengths. At the start of the campaign six regiments of pezhetairoi were included in the expeditionary army, but during the campaign a seventh taxis was added using reinforcements from Macedonia. It is not known whether this seventh regiment was also territorially recruited or that men from different districts were grouped together.

The pezhetairoi formed the main heavy infantry force of the Macedonian army. The training and armament of these heavy foot soldiers were much more flexible than that of the hoplites in most Greek city states. Equipment and tactics could be adjusted to suit different situations. Armed with the hoplite shield and a spear of normal length the foot companions were capable of deployment in a classical Greek hoplite phalanx. In addition these soldiers could be equipped with a long pike requiring the use of both hands, the famous sarissa, and a different rimless shield hanging from the shoulder to fight in the distinctive Macedonian variant of the phalanx. On a number of occasions these soldiers were also equipped with light javelins instead of spears or pikes. The various sources give different descriptions of the defensive equipment used by the pezhetairoi. It is very probable that this equipment like the offensive weaponry was adapted to suit differing tactical requirements. A helmet appears to have been an item regularly worn by the foot companions, but additional protection in the guise of metal greaves or a kind of body armour is also mentioned. As worn out armour was burned in India, the body armour was probably constructed of linen, felt or leather. Linen or leather corselets of the same cut as Greek hoplite types are depicted on the so-called Alexander sarcophagus and may have been standard issue. If later Hellenistic practice reflected earlier conditions the officers and NCO’s forming the front rank of the formation may have been equipped with metal cuirasses. Body armour of any sort was very uncomfortable in hot weather. On some occasions at least part of the troops may have discarded body armour for this reason. Experiments were also made with armour that offered only frontal protection.

In addition to the pezhetairoi existed an elite formation of hypaspistai or shield bearers. These men can almost certainly be identified with the so-called argyraspides or silver shields from the later part of Alexander’s reign. These soldiers were not recruited on a territorial basis, but selected individually on merit from the taxeis of the pezhetairoi. The hypaspistai numbered three thousand men organised in three subunits of each a thousand soldiers. Although constituting a picked force among the Macedonian infantry one of these battalions, the agema, had a higher prestige than the other two. A modest number of soomatophylakes recruited among the Macedonian nobility was attached to the hypaspistai , which were selected among those of common birth. As these units were not like the taxeis of foot companions depending on replacements originating from a particular district the hypaspistai are likely to have maintained their establishment strength throughout the campaigns of Alexander the Great by constant selection of picked men from the other regiments of Macedonian heavy infantry.

Tactics and equipment of the hypaspistai were probably similar to those of the pezhetairoi, but as an elite formation they were often used for special assignments. In set piece engagements the shield bearers were generally deployed on the dangerous place of honour at the right flank of the heavy infantry line. Several modern authors assume that these soldiers usually wore lighter equipment in battle than the foot companions, but clear indications for a different armament are absent from the ancient sources. Their frequent use on special duties however meant that the hypaspistai were more likely to carry lighter arms and equipment when not deployed in a set piece battle.

Besides the heavy infantry of foot companions and shield bearers there was also native Macedonian light infantry enrolled in the army of Alexander. These were made up of javelineers, archers and slingers. Most light infantry was however not recruited in Macedonia proper. The javelin armed Agrianoi stemmed from the neighbouring kingdom of Lagarus. These Agrianoi formed an elite among Alexander’s forces and were often employed on dangerous missions. On occasion these troops were used as hamippoi to strengthen the Macedonian cavalry. An additional 7000 strong contingent of Thracians served as peltastai, shield bearing skirmishers. These Thracians were however not so much selected for their military value, but rather to limit the risk of an uprising in their homelands. The Macedonian archers were supplemented by mercenary bowmen from Crete.

The Macedonian allies

An important contingent in the army of Alexander the Great was the Thessalian cavalry that served the Macedonian king because he was tagos or military leader of Thessalia as well. These horsemen generally operated in battle as the heavy cavalry wing deployed on the left flank of the army. Eight territorially recruited ilai were selected to join the Asian campaign. The Pharsalian ilè had much the same status amongst these squadrons as the royal ilè among the Macedonian companion cavalry. This particular unit may have had a higher establishment strength than the usual two hundred troopers. In contrast to the wedge deployment used by Macedonian and Thracian horsemen the cavalry of Thessaly usually favoured a rhomboid formation. After the war of revenge on the Persian empire was officially brought to an end those Thessalian cavalrymen that opted not to return home were integrated in the reorganised units of the Macedonian hetairoi.

Detachments of forces were also sent by the city states of the Corinthian league to join the retribution campaign against the Persians. These soldiers belonged in part to the professional soldiers of the small standing armies maintained by the Greek poleis. It is not known to what extent the armament and equipment of these forces varied, but modern literature on the subject assumes that the majority of these troops served as hoplites. The equipment of these hoplites was probably no longer as light as it had been at the turn of the century. Vase paintings and sculptures seem to point to a renewed widespread use of metal body armour by Greek hoplites. In addition to the infantry troops some city states also sent small numbers of horsemen to join the Macedonian army. The troops sent by the Corinthian league had no significant role in any of the battles fought by Alexander. At the end of the official vengeance campaign against the Achaemenid empire these forces were excused further duty. Although the majority of men returned to their cities, some took service as mercenaries in Alexander’s army.

Greek mercenaries were also used in the Macedonian expeditionary army. Though these forces were mostly employed for garrison duty in the conquered provinces part of the mercenaries served in the field army. The infantry was composed of both hoplites and peltastai. A number of small mercenary horsemen played an important role in the field army cavalry. Mercenary troops were also hired among the population of the conquered territories of the Persian empire and India. Some of these indigenous forces consisted of mounted javelineers and horse archers, others served as light infantry skirmishers. At the end of Alexander’s reign Asiatic troops were levied and equipped and trained on the Macedonian model.

The Macedonian command structure

At the head of the Macedonian army chain of command was Alexander the Great himself. The senior officers were partly selected from those that had been brought up with the Macedonian king, though part of the high command consisted of men who had made careers during the reign of Philippus II. Most prominent among the last group was Parmenio, said by Philippus to have been his only general. The relationship between Parmenio and Alexander is traditionally portrayed by the ancient sources to have been plagued by constant differing of opinions. This image can be corrected by careful reading of the available texts. The course of action advised by Parmenio appears to have adopted by Alexander both before Gaugamela and the battle at the Granicus.

The planning and preparation of battles was of the utmost importance. Because of the very limited means of communicating orders in battle, much depended on the instructions given to subordinate commanders beforehand. The sources indicate the convening of a general staff meeting to discuss plans and preparations. Good reconnaissance and reliable intelligence were vital for proper planning of the engagements ahead. Though a system of scouts and spies was employed to furnish Alexander with much needed information, intelligence required the constant personal attention of the commander in chief himself. Before the battle of Gaugamela the Macedonian king went on a reconnaissance foray in person to obtain first-hand information.

The officer corps was predominantly structured on territorial divisions. Officers of the various units of hetairoi and pezhetairoi were usually, but not invariably selected from the nobles of the same district as the common soldiers. Junior officers appear to have largely specialised in command of either horse or foot, but senior commanders could be tasked with both infantry and cavalry commands. During the campaigns the importance and prestige of cavalry commands was reinforced. Many officers must have been personally acquainted with their commander in chief through prior service in the paides basilikoi, the royal pages, or the soomatophylakes basilikoi, the royal bodyguards. The selection of senior commanders especially was not always directly related to their military qualities, but was often connected to personal favour, blood ties and political reliability.

The command of an army of many different nationalities posed a number of problems. The various troops spoke different languages and dialects. Officers commanding contingents of foreign forces were probably required to master the use of the Greek language and some rudimentary knowledge of the basic Greek orders may have been taught to their subordinates. The language barriers were not the only communication problems. Armies in Antiquity lacked effective means of long range communication. Commands by word of mouth had very limited range in the noise of battle. Indications for the use of musical instruments to communicate orders in battle are limited for the army of Alexander. The army also lacked an equivalent of the Roman army standards that could be employed to visually communicate simple orders to the troops. The use of such visual signals was probably very limited anyway because of the enormous clouds of dust raised by the masses of men and horses. Mounted messengers were the main if not fully reliable means of communication on long ranges. Because of these flawed means of communications between the various parts of the battle line the dependence on plans made beforehand and able subordinate commanders was very great. A commander in chief had only effective control over the units in his immediate vicinity and lacked an overall view of the situation. The general staff meetings before an engagement were therefore vital for the coordination of the army’s actions.

The battle tactics of the army of Alexander were generally aimed to force a rapid decision. The attack of the Macedonian forces was generally made in an oblique battle formation with an advanced right flank and a refused left wing. A fierce charge of the heavy horse on a small portion of the enemy’s forces was intended to break the morale of the enemy and create panic among units not yet engaged in combat. Success depended to a large extent on sapping the morale of an opponent. The use of surprise was an important means to undermine the confidence of the enemy. Unexpected manoeuvres were employed to surprise the opposing forces at the Granicus, Issus and the Hydaspes. It was also important to engage the enemy when his forces were fatigued by long marches or lack of sleep.

Special thanks to Sander van Dorst, who is the author of this text.

Rank structure of the imperial Roman army

Legionary rank structure


Tiro (recruit). He was not yet subjected to full rigours of military discipline untill he passed out and was registered as a real soldier, no regular pay so presumably living of his enlistment bounty or viaticum.

Lower ranks

Miles (private) also: munifex (fatigue worker) or gregralis / gregarius (literally: herd animal). He was on basic pay and eligible for fatigue duties. Legionary cavalrymen had higher basic pay, as did their NCO’s due to the higher cost of equipment and may have had immunis status as a rule, though this is not certain.

Discens (trainee). Private in training for special function, basic pay and eligible to fatigue duties.

Immunis (immune (from fatigues)). Attested from the second century AD onwards, the late first century opera vacans may have been an earlier designation for the same position. Specialist with basic pay and immunity from certain fatigue duties, could apparently be granted this status both indefinitely and temporarily as one inscription lists an immunis perpetuus.

There is a lot of confusion regarding rank and function in the Roman army. Some specialist positions could be held by men of various rank (eg exercitator or cavalry instructor) and this has led to some authors assigning NCO status to all men holding a specialist position, even in cases that this cannot be confirmed by direct evidence. It is important to be weary of functions that could be held by privates, NCO’s and subaltern officers alike.

Non commissioned officers

Sesquiplicarius (NCO on basic pay and a half). Junior NCO. Example: tesserarius (NCO in charge of watch words) and vexillarius or vexillifer (flag bearer).

Duplicarius (NCO on double basic pay). Senior NCO. Examples: optio centuriae (rearrank officer), signifer (standardbearer), cornicularius (administrator), aquilifer (eagle standard bearer). Epigraphic evidence for career structures does not allow to distinguish a coherent system of promotion between these first three different duplicarius functions, so perhaps there were either frequently changes in status between the three of them or all three were of identical seniority. Note that optio (‘chosen man’) could also be used for mere privates with special duties rather than real NCO’s leading to some confusion in determining career patterns.

Triplicarius (NCO on triple basic pay). Senior NCO. Evidence for this rank is very rare and it may have existed for only a brief while.

Salararius or salaratus. Some soldiers with special skills served against non standard service conditions, either as mercenaries or reenlisted veterans, and received salaria instead of regular stipendia, a special rate of pay.

Duplicarii and sesquiplicarii combined became known as principales from the second century AD on. Cavalry NCO’s received double the higher cavalryman’s basic pay (stipendia equestria). Discharge benefits, praemia or commoda, and special bonuses, donativa, followed the same rates as basic pay.

Subaltern officers

Centurio (‘commander of hundred’, officer in command of a centuria) also ordinarius or title derived from original place in the battle order. There was some variation in seniority and remuneration between these officers. Those with prior in their titles (hastatus priorprinceps prior and pilus prior) led the manipuli with officers with posterior in their titles (hastatus posteriorprinceps posterior and pilus posterior) acting as deputies. Pili could also be named triarius, though this was very rare under the empire (one certain case, one possible). It is thought that the pilus prior was in command of a legion’s cohort. Pay for all these officers was at least fifteen times that of a ranker. The socalled primi ordines, the centurions of the first cohort, had much higher status and pay (estimated at at least thirty times basic pay) than the other officers. The primus pilus was the most senior centurion and received 60 times basic pay plus entry into the equestrian order after completion of his stint.

In addition to the 59 or 60 ordinarii (those actually commanding an ordo or centuria of the legion) there was an unknown number of supernumerarii attached to each legion. These officers had special functions in the legionary cavalry, military intelligence, medical service, elite legionary infantry and various other postings in the governor’s staff or imperial horse guards.

The centurions were either equestrians or curiales directly commissioned from civilian life or had started out as buck privates and earned their position by serving in NCO postings in the legion or the imperial praetorian guard. Directly commissioned equestrian officers may have had different pay as they received salaria instead of the usual stipendia. Note that there were, as far as can be established with our present sources, no decuriones for the imperial era legionary horse in contrast with the republican legion. Apparently these cavalrymen were now commanded either by centurions or NCO’s.

Senior officers

Tribunus. There were six of these officers to a legion and usually there were five equestrian tribuni angusticlavii and one senatorial tribunus laticlavius, named thin – or broad striped after the purple lines on their tunics that indicated their social status. The last one was had higher status and functioned as second-in-command of the legion. The equestrians were generally career officers with previous commands over auxiliary foot regiments, for senatorial youths this was often their first post. Some tribuni served only six month tours rather than the more usual 1-3 years. A few served two or even rarer three stints of duty. Though modern works often ascribe these officers purely administrative tasks, the source material indicates that these had by no means replaced their tactical command function.

Praefectus castrorum. This camp commandant usually had held the post of senior centurion and was in charge of a host of tasks. Of equestrian status, he was third in the chain of command, except in Egypt and later also in special circumstances when this officer acted as praefectus legionis, sometimes with the additional designation agens in vice legati, acting in place of a legate.

Legatus legionis. A senatorial officer who generally had seen prior service as tribunus and was placed in charge of the legion. Some special cases included equestrians elevated to senatorial status with previous commands in the auxilia.

Auxiliary rank structure

Auxiliary rankers, NCO’s and subaltern officers

Generally the same as for the legions. The equites cohortales, cavalrymen attached to a cohors equitata, an infantry formation with organic cavalry component, had higher status and pay then the foot soldiers, but inferior to that of the equites alares, the troopers of the cavalry regiments. A peculiarity of auxiliary cavalry noncom titles is that they were often just named after their pay grade rather than their function. Auxiliary cavalry turmae were led by decuriones, who were of similar rank to infantry centuriones. Some similar type of ranking structure may have existed for auxiliary decuriones and centuriones, but surviving details are sketchy. Since there were auxiliary ordinarii perhaps some auxiliary units had supernumerary officers as well. Auxiliary infantrymen received either five sixths or equal amounts compared to the pay of legionaries, cavalrymen received more. Cavalry is not attested as having built anything themselves, so perhaps they had all status of immunis or were excused certain types of menial tasks. Many auxiliary noncoms and subaltern officers were either transferred legionaries or otherwise Roman citizens rather thanperegrini (freeborn unenfranchised provincials).

Auxiliary officers

Praefectus cohortis. Commander of an infantry unit or infantry unit with organic horsemen. Usually the first post in the equestrian military career (tres militiae) and for some the last, it appears to have been of equal status and remuneration as the legionary centurionate. Men with good service records or influential friends could go on to a legionary tribunate or post of tribunus cohortis. A post of subpraefectus is known from the early principate, though its precise details are unclear.

Tribunus cohortis. Commander of a unit originally raised from Roman citizens or of milliary (thousand strong) strength. Usually a second post in the equestrian military career.

Praefectus alae. Commander of a quingenary (five hundred strong) cavalry regiment. Usually the third post in the equestrian military career, though for a short period the second. The post of praefectus alae of a milliary unit brought great prestige and was the extraordinary militia quarta (fourth post in equestrian army career).

Most equestrian commands lasted 2 to 4 years, though it could in some cases be held for 10 years or more. For most equestrians military serice seems to have been a professional career, though others only opted for a short military term in an otherwise civilian career. Some equestrian’s opted for a legionary centurionate rather than an auxiliary prefecture, which is thought to have offered more secure employment.


Several terms for commanders were not linked to an actual military rank and could be held by men of varying status.

Praefectus fabrum. Commanders of artisans are attested, though little is clear about their precise place in the military hierarchy

Praepositus. This term signifies a person placed in charge and could be applied to a wide range of functions held by men of various ranks from privates with a special task to senior commanders in charge of entire army groups.

Dux. A very general term for commanders of varying rank and status.

Magister. The term of master was like praepositus very wide in its use from mere privates to the most senior commanders.

Imperator. This was a special title given to commanders who had been hailed as such by their troops after a victorious battle. Under the empire it was only used by the emperor himself and his designated successor or collegue.

Special thanks to Sander van Dorst, who is the author of this text.