- Plural of legion
The Roman Legion (from Latin legio "military levy, conscription", from legere — "to choose") is a term that can apply both as a transliteration of legio ("conscription" or "army") to the entire Roman army and also, more narrowly (and more commonly), to the heavy infantry that was the basic military unit of the ancient Roman army in the period of the late Roman Republic and the Roman Empire. In this latter meaning, it consisted of several cohorts of heavy infantry known as legionaries. It was almost always accompanied by one or more attached units of auxiliaries, who were not Roman citizens and provided cavalry, ranged troops and skirmishers to complement the legion's heavy infantry.
The size of a typical legion varied widely throughout the history of ancient Rome, with complements of 4,200 legionaries and 300 equites in the republican period of Rome, (the infantry were split into 35 maniples of 120 legionaries each), to 5,200 men plus auxiliaries in the imperial period (split into 10 cohorts, 9 of 480 men each, plus the first cohort holding 800 men).
As legions were not standing armies until the Marian reforms (c. 107 BC), and were instead created, used, and disbanded again, several hundred legions were named and numbered throughout Roman history. To date, about 50 have been identified. In the time of the Early Roman Empire, there were usually about 25-35 standing legions plus their Auxiliaries, with more raised as needed. See List of Roman legions for a catalogue of known late republic, early Empire and late Empire legions, with dates in existence, emblem and locations of deployment.
Due to the enormous military successes of the Roman Republic and the Roman Empire the legion has long been regarded as the prime ancient model for military efficiency and ability.
Roman kings (to c.500 BC)In the early years of the Roman Kingdom and the Roman Republic, they did not use legions and instead used centuries of one hundred men which were banded together in random formats and only served the one who had hired them. In the Roman Empire the legions became, although the largest, only one part of the army (predominantly heavy infantry). But in the Roman Kingdom and Roman Republic up until the 2nd century BC, the centuries could be made of light troops and cavalry whose roles would later be taken on by allied troops. During this period, the massive Greek phalanx was the mode of battle. Roman soldiers would have thus looked much like Greek hoplites.
Much of Roman history of this era is founded on legends, but it is believed that during the reign of Servius Tullius, the census (the counting of the people) was introduced. With this, all Roman able-bodied, property-owning male citizens were divided into five classes for military service based on wealth, soldiers having to acquire their own weapons and equipment. These classes were further organized into units of 100 called centuries (who also had a centurion, a second in command and a standard bearer).
Joining the army was both a duty and a distinguishing mark of Roman citizenship: during the entire pre-Marian period the wealthiest land owners performed the most years of military service, since these would have had the most to lose should the state have fallen. The first class was armed in the fashion of the hoplite with spear, sword, helmet, breast plate and round shield (called clipeus in Latin, similar to the Greek aspis, also called hoplon); there were 82 centuries of these of which 2 were trumpeteer. The second and third class also acted as spearmen, but with reduced armour, and the larger oval or rectangular shield. The fourth class could afford no armour, perhaps a small shield, and was armed with spear and javelin. All three of the latter classes made up about 26 centuries. The fifth and final class was composed only of slingers. There were 32 of these of which 2 were engineers. The army officers as well as the cavalry were drawn from leading citizens who enrolled as equestrians (equites). (The equites were later put in smaller groups of 30 and were commanded by decurions (which strangely means commander of ten)), there were 18 centuries of equites.
Tactics were no different from those of the early Greeks and battles were joined on a plain. Spearmen would then deploy themselves in tightly packed rows. The members of each row closed to form a shield wall, their spears pointed forwards, and charged the enemy supported by their javelin throwers and slingers: the cavalry pursued the enemy, and sometimes dismounted to support the infantry in dire situations. It was a cumbersome military unit to manoeuvre, and easily defeated by mountain tribes such as Volsci or Samnites in rough terrains.
Early civilian authorities, called praetors, doubled as military leaders during the war season; lasting from spring to autumn. A formal war declaration included a religious ceremony that ended in the throwing of a ceremonial javelin into the enemy's territory to mark the start of hostilities.
Roman Republic (509-107 BC)
At some point, possibly in the beginning of the Roman Republic after the kings were overthrown, the legio was subdivided into two separate legions, each one ascribed to one of the two consuls. In the first years of the Republic, when warfare was mostly concentrated on raiding, it is uncertain if the full manpower of the legions was summoned at any one time. Legions became more formally organized in the 4th century BC, as Roman warfare evolved to more frequent and planned operations, and the consular army was raised to two legions.
In the Republic, legions had an ephemeral existence. Except for Legio I to IV, which were the consular armies (two per consul), other units were levied by campaign. Rome's Italian allies were required to provide a legion to support each Roman Legion.
In the middle of the Republic, legions were composed of the following units:
- Equites (cavalry): The cavalry was originally the most prestigious unit, where wealthy young Roman men displayed their skill and prowess, laying the foundation for an eventual political career. Cavalry equipment was purchased by each of the cavalrymen and consisted of a round shield, helmet, body armour, sword and one or more lances. The cavalry was outnumbered in the legion. In a total of circa 3000 men, (plus the velites that normally enlarged the number to about 4200), the legion had only around 300 horsemen, divided into 10 units of 30 men. These men were commanded by decurions. In addition to heavy cavalry, there would be the light cavalry levied from poor citizens and wealthy young citizens not old enough to be in the hastati or the equites. In battle, they were used to disrupt and outflank enemy infantry formations and to fight off enemy cavalry. In the latter type of engagement they would often (though not always) dismount some or all of the horsemen to fight a stationary battle on foot, an unusual tactic for the time, but one that offered significant advantages in stability and agility in a time before stirrups.
- Velites (light infantry): The velites were mainly poorer citizens who couldn't afford to equip themselves properly. Their primary function was to act as skirmishers - javelin-throwers who would engage the enemy early in order either to harass them or to cover the movement of troops behind them. After throwing their javelins they would retreat through the gaps between the maniples, screened from the attack of the enemy by the heavy infantry lines. With the shortage of cavalry in the army of the early to mid Republican army, the velites were also used as scouts. They did not have a precise formal organization or formation.
infantry: This was the principal unit of the legion. The heavy
infantry was composed of citizen legionaries that could afford the
equipment composed of an iron helmet, shield, armour and pilum, a heavy javelin whose range
was about 30 meters. After 387 the preferred weapon for the hastati
and principes was the gladius, a short sword. Their
hobnailed sandals (caligae) were also an effective
weapon against a fallen enemy. Prior to the Marian reforms (see
below) the heavy infantry was subdivided, according to the
legionaries' experience, into three separate lines:
- The hastati (sing. hastatus) were the youngest, less reliable troops.
- The principes (sing. princeps), men in their prime ages (late twenties to early thirties).
- The triarii (sing. triarius) were the veteran soldiers; only in extreme situations would they be used in battle and rested one knee down when unengaged. They were equipped with spears rather than the pilum and gladius (the hastati and pricipes stopped using spears in 387 B.C.), so they fought in a phalanx, and the sight of an advanced shield wall in front of them discouraged exultant enemies pursuing hastati and principes. To fall upon the triarii was a Roman idiom meaning to use ones last resort.
Each of these three lines was subdivided into maniples, each consisting of two centuries of 60 men commanded by the senior of the two centurions. Centuries were normally 60 soldiers each at this time in the hastati and principes (no longer 100 men), with 120 strong maniples. There were generally 10 maniples of hastati, 10 maniples of principes and 10 of triarii which had two half strength centuries of 30 men, plus about 1200 velites and 300 cavalry which made up 10 units - 30 men strong. This gave the mid Republican legion a nominal strength of about 4500 men. Later on when the legions undertook the Marian reforms and was made up of 80 strong centuries each century had its standard and was made up of ten units called contubernia. In a contubernium, there would be eight soldiers who shared a tent, millstone, a mule and cooking pot (depending on duration of tour). Because maniples were their main tactical elements, the legions of the early Republic are sometimes referred to as Manipular legions.
Late Republic (107-30BC)
See also List of Roman legions for details of notable late Republican legions
Following the Marian reforms of the 2nd century BC, the legions took on the second, narrower meaning that is familiar in the popular imagination as close-order citizen heavy infantry.
At the end of the 2nd century BC Gaius Marius reformed the previously ephemeral legions as a professional force drawing from the poorest classes, enabling Rome to field larger armies and providing employment for jobless citizens of the city of Rome. However, this put the loyalty of the soldiers in the hands of their general rather than Rome itself. In this period all Italian regions obtained full Roman citizenship and provided a larger basis for the army, supplemented by poor urban Romans.
The legions of the Late Republic and Early Empire are often called Marian legions. Following the Battle of Vercellae in 101 BC, Marius granted all Italian soldiers Roman citizenship. He justified this action to the Senate by saying that in the din of battle he could not distinguish Roman from ally. This effectively eliminated the notion of allied legions; henceforth all Italian legions would be regarded as Roman legions, and full Roman citizenship was open to all the regions of Italy. Thus the three different types of heavy infantry were replaced by a single, standard type based on the Principes: armed with two heavy javelins called pila, the short sword called gladius, chain mail (lorica hamata) or banded armour (lorica segmentata), helmet and rectangular shield (scutum).
The role of allied legions would eventually be taken up by contingents of allied auxiliary troops, called Auxilia. Each legion had an auxilia of similar size, which contained specialist units, engineers and pioneers, artillerymen and craftsmen, service and support personnel and irregular units made up of non-citizens, mercenaries and local militia. These were usually formed into complete units such as light cavalry, light infantry or velites, and labourers. There was also a reconnaissance squad of 10 or more light mounted infantry called speculatores who could also serve as messengers or even as an early form of military intelligence service.
As part of the Marian reforms, the legions' internal organization was standardized. Each legion was divided into cohorts. Prior to this, cohorts had been temporary administrative units or tactical task forces of several maniples, even more transitory than the legions themselves. Now the cohorts were ten permanent units, composed of 6 and in the case of the first cohort 8 centuries each led by a centurion assisted by an optio, a soldier who could read and write. These came to form the basic tactical unit of the legions. The senior centurion of the legion was called the primus pilus, a career soldier and advisor to the legate that sometimes was promoted to the higher rank.
Every legion had a baggage train of 640 mules or about 1 mule for every 8 legionaries. To keep these baggage trains from becoming too large and slow, Marius had each infantryman carry as much of his own equipment as he could, including his own armour, weapons and 15 days' rations, for about 25-30 kg (50–60 pounds) of load total. To make this easier, he issued each legionary a forked stick to carry their loads on their shoulders. The soldiers were nicknamed Marius' Mules due to the amount of gear they had to carry themselves. This arrangement allowed for the supply train to become detached from the main body of the legion, thus greatly increasing the army's speed while on the march.
A typical legion of this period had 5,120 legionaries as well as a large number of camp followers, servants and slaves. Legions could contain as many as 6,000 fighting men when including the auxiliaries, although much later in Roman history the number was reduced to 1,040 to allow for greater mobility. Numbers would also vary depending on casualties suffered during a campaign; Julius Caesar's legions during his campaign in Gaul often only had around 3,500 men.
Tactics were slightly different from the past, but largely improved due to the professional training of the soldiers.
After the Marian reforms, and throughout the history of Rome's Late Republic, the legions played an important political role. By the 1st century BC the threat of the legions under a demagogue was recognized. Governors were not allowed to leave their provinces with their legions. When Julius Caesar broke this rule, leaving his province of Gaul and crossing the Rubicon into Italy, he precipitated a constitutional crisis. This crisis and the civil wars which followed brought an end to the Republic and led to the foundation of the Empire under Augustus in 27 BC.
Early Empire (30 BC-284 AD)
For political and economic reasons, Augustus reduced the number of legions from nearly 50 at the end of his war against Mark Antony to only 28 which decomposed to 25 after the Battle of Teutoburg Forest in which 3 legions were slaughtered. Generals during the recent Republican civil wars had formed their own legions and numbered them as they wished. When these wars ended, Augustus was left with around fifty legions, with several double counts (multiple Legio Xs for instance). Beside streamlining the army, and regulating the soldiers' pay, he corrected these numbering anomalies. During this time, there was a high incidence of Gemina (twin) legions, where two legions were consolidated into a single organization (and was later made official and put under a dux and six duces).
At the same time, he greatly increased the number of auxiliaries to the point where they were equal in number to the legionaries. He also created the Praetorian Guard along with a permanent navy where served the liberti, or freed slaves.
Augustus' military policies proved sound and cost effective, and were generally followed by his successors. These emperors would carefully add new legions, as circumstances required or permitted, until the strength of the standing army stood at around 30 legions. With each legion having 5,120 legionaries usually supported by an equal number of auxiliary troops, the total force available to a legion commander during the Pax Romana probably ranged from 153,600 downwards, with the more prestigious legions and those stationed on hostile borders or in restive provinces tending to have more auxiliaries. Some legions may have even been reinforced at times with units making the associated force near 15,000–16,000 or about the size of a modern division.
Throughout the imperial era, the legions played an important political role. Their actions could secure the empire for a usurper or take it away. For example, the defeat of Vitellius in the Year of the Four Emperors was decided when the Danubian legions chose to support Vespasian.
In the empire, the legion was standardized, with symbols and an individual history where men were proud to serve. The legion was commanded by a legatus or legate. Aged around thirty, he would usually be a senator on a three year appointment. Immediately subordinate to the legate would be six elected military tribunes — five would be staff officers and the remaining one would be a noble heading for the Senate (originally this tribune commanded the legion). There would also be a group of officers for the medical staff, the engineers, record-keepers, the praefectus castrorum (commander of the camp) and other specialists such as priests and musicians.
Late Empire (from 284)
In the Later Roman Empire, the number of legions was increased and the Roman Army expanded. There is no evidence to suggest that legions changed in form before the Tetrarchy, although there is evidence that they were smaller than the paper strengths usually quoted. The final form of the legion originated with the elite legiones palatinae created by Diocletian and the Tetrarchs. These were infantry units of around 1,000 men rather than the 5,000, including cavalry, of the old Legions. The earliest legiones palatinae were the Lanciarii, Joviani, Herculiani and Divitenses.
The 4th century saw a very large number of new, small legions created, a process which began under Constantine II. In addition to the elite palatinae, other legions called comitatenses and pseudocomitatenses, along with the auxilia palatina, provided the infantry of late Roman armies. The Notitia Dignitatum lists 25 legiones palatinae, 70 legiones comitatenses, 47 legiones pseudocomitatenses and 111 auxilia palatina in the field armies, and a further 47 legiones in the frontier armies. Legion names such as Honoriani and Gratianenses found in the Notitia suggest that the process of creating new legions continued through the 4th century rather than being a single event. The names also suggest that many new legions were formed from vexillationes or from old legions.
According to the late Roman writer Vegetius' De Re Militari, each century had a ballista and each cohort had an onager, giving the legion a formidable siege train of 59 Ballistae and 10 Onagers each manned by 10 libritors (artillerymen) and mounted on wagons drawn by oxen or mules. In addition to attacking cities and fortifications, these would be used to help defend Roman forts and fortified camps (castra) as well. They would even be employed on occasion, especially in the later Empire, as field artillery during battles or in support of river crossings.
Legionary officersAside from the rank and file legionary (who received the base wage of 10 asses a day or 225 denarii a year), the following list describes the system of officers which developed within the legions from the Marian reforms (104 BC) until the military reforms of Diocletian (circa 290).
- Legatus legionis: The overall legionary commander. The post was usually filled by a senator, appointed by the emperor, who held command for 3 or 4 years, although he could serve for a much longer period. In a Roman province with only one legion, the legatus was also the provincial governor and in provinces with multiple legions, each legion had a legatus and the provincial governor had overall command of them all.
- Tribunus laticlavius: Named for the broad striped toga worn by men of senatorial rank, this tribune was appointed by the emperor or the Senate. Though generally quite young and less experienced than the tribuni angusticlavii, he served as second in command of the legion, behind the legate. Due to his age and inexperience he was not the actual second in command in battle, but if the legate died he would take command of the legion. This tribunate was often a first, but optional, step in a young man's senatorial career (see cursus honorum).
- Praefectus castrorum: The camp prefect. Generally he was a long serving veteran who previously had served as primus pilus and finished his 25 years with the legions. He was the battle commander and actual second in command of the legion, although he was of lower social status than the tribunii.
- Tribuni angusticlavii: Each legion had five military tribunes of equestrian (knight) class citizens. They served as staff officers of the legion, but also performed duties such as commander of a detachment from the legion.
- Primus pilus: The "first spear" (literal translation) or "first centurion" was the commanding centurion of the first cohort and the senior centurion of the entire legion. This was the highest rank that a career officer could achieve in the 25 years he served. When the primus pilus retired he would most likely gain entry into the equestrian class. He was paid 60 times the base wage.
- Pilus prior: The "superior spear" or "ranking centurion" where the first centurions of each of the ten Cohorts were called pilus prior and were the most senior centurion within their respective cohort. While the legion was in battle formation, the Pilus Prior was given command of the entire cohort, with each of the centurions as his lieutenants. The Primus Pilus was also a Pilus Prior, and the most senior of all the centurions within the legion. These positions were usually held by experienced veteran soldiers who had been moved up within the ranks. This rank is subordinate to the Primus Pilus.
- Primi ordines: The "first class" where the five centurions of the first cohort, and included the primus pilus. They, excluding the primus pilus, were paid 30 times the base wage. This rank is senior to all other centurions, save the primus pilus and pilus prior.
- Centuriones: Each legion had 59 or 60 centurions, one to command each century of the 10 cohorts. They were the backbone of the professional army and were the career soldiers who ran the day to day life of the soldiers and issued commands in the field. They were generally moved up from the ranks, but in some cases could be direct appointments from the Emperor or other higher ranking officials. The cohorts were ranked from the first to the tenth and the century within each cohort ranked from 1 to 6, with only 5 centuries in the first cohort (for a total of 59 centurions and the primus pilus). The century that each centurion commanded was a direct reflection of his rank: command of the first century of the first cohort was the highest, and the 6th century of the 10th cohort was the lowest. Comparing the centurion to modern military ranks is problematic, as the century falls somewhere between modern platoon size (30-40 soldiers, depending on nationality), and modern company size (100-200 soldiers, depending on nationality). This would make a centurion the approximate equivalent of a British Army Major, or in the United States Army a Captain. Paid ten times the basic wage.
- Optio: One for each centurion (59-60), they were appointed by the centurion from within the ranks to act as his second in command. Paid twice the basic wage.
- Duplicarius: An officer paid double the basic pay.
- Tesserarius: (Guard commander) Again there were 59 of these, or one for each century. They acted seconds to the Optios. Paid one and a half times the basic wage.
- Decurion: Commanded a cavalry unit of 10 to 30 Eques legionis.
- Decanus: Commanded a contubernium or eight man tent party.
Special duty posts
- Aquilifer: A single position within the legion. The aquilifer was the legion's Standard or Aquila (eagle) bearer and was an enormously important and prestigious position. Losing the aquila was considered a great dishonour. This post therefore had to be filled with steady veteran soldiers, with an excellent understanding of the tactics of the legion. He was paid twice the basic wage.
- Signifer: Each century had a signifer (59). He was responsible for the men's pay and savings, and the standard bearer for the centurial signum, a spear shaft decorated with medallions and often topped with an open hand to signify the oath of loyalty taken by the soldiers. It was this banner that the men from each individual century would rally around. A soldier could also gain the position of discentes signiferorum, or standard bearer in training. He was paid twice the basic wage.
- Cornicen (Horn blower): Worked hand in hand with the signifer drawing the attention of the men to the centurial signum and issuing the audible commands of the officers.
- Imaginifer: Carried the standard bearing the image of the Emperor as a constant reminder of the troops' loyalty to him.
PayFrom the time of Gaius Marius onwards, legionaries received 225 denarii a year; this basic rate remained unchanged until Domitian, who increased it to 300 denarii. In spite of the steady inflation during the 2nd century, there was no further rise until the time of Septimius Severus, who increased it to 500 denarii a year. This salary would be supplemented by the booty taken in a campaign.
All legionary soldiers would also receive a sizeable sum of money on the completion of their term of service: 3000 denarii from the time of Augustus and/or a plot of good farmland (good land was in much demand). Later, under Caracalla, the praemia increased to 5000 denarii.
SymbolsFrom 104 BC onwards, each legion used an aquila (eagle) as its standard symbol. The symbol was carried by an officer known as aquilifer, and its loss was considered to be a very serious embarrassment, and often led to the disbanding of the legion itself. Normally this was due to the fact that any legion incapable of regaining its eagle in battle was so severely mauled it was no longer a workable fighting force.
In Gallic War (Bk IV, Para. 25), Julius Caesar describes an incident at the start of his first invasion of Britain in 55BC that illustrated how fear for the safety of the eagle could drive Roman soldiers. When Caesar's troops hesitated to leave their ships for fear of the Britons, the aquilifer of the tenth legion threw himself overboard and, carrying the eagle, advanced alone against the enemy. His comrades, fearing disgrace, 'with one accord, leapt down from the ship' and were followed by troops from the other ships.
With the birth of the Roman Empire, the legions created a bond with their leader, the emperor himself. Each legion had another officer, called imaginifer, whose role was to carry a pike with the imago (image, sculpture) of the emperor as pontifex maximus.
Each legion, furthermore, had a vexillifer who carried a vexillum or signum, with the legion name and emblem depicted on it, unique to the legion. It was common for a legion to detach some sub-units from the main camp to strengthen other corps. In these cases, the detached subunits carried only the vexillum, and not the aquila, and were called, therefore, vexillationes. A miniature vexillum, mounted on a silver base, was sometimes awarded to officers as a recognition of their service upon retirement or reassignment.
Civilians could also be rewarded for their assistance to the Roman Legions. In return for outstanding service, a citizen was given an arrow without a head.
DisciplineThe military discipline of the legions was quite harsh. Regulations were strictly enforced, and a broad array of punishments could be inflicted upon a legionary who broke them. Many legionaries became devotees in the cult of the minor goddess Disciplina, whose virtues of frugality, severity and loyalty were central to their code of conduct and way of life.
- Castigatio - being hit by the centurion with his staff or animadversio fustium(Tac. Annals I, 23)
- - Reduction of rations or to be forced to eat barley instead of the usual grain ration
- Pecunaria multa - Reduction in pay, fines or deductions from the pay allowance
- - Flogging in front of the century, cohort or legion
- - Whipping with the flagrum (flagellum, flagella), or "short whip" — a much more brutal punishment than simple flogging. The "short whip" was used for slave volunteers, volones, who comprised the majority of the army in the later years of the Roman Empire.
- Gradus deiectio - Reduction in rank
- Missio ignominiosa - Dishonourable discharge
- - Loss of time in service advantages
- Militiae mutatio - Relegation to inferior service or duties.
- Munerum indictio - Additional duties
- Fustuarium — a sentence for desertion or dereliction of duty. The legionary would be stoned or beaten to death by cudgels, in front of the assembled troops, by his fellow soldiers, whose lives had been put in danger. Soldiers under sentence of fustuarium who escaped were not pursued, but lived under sentence of banishment from Rome.
- Decimation — a sentence carried out against an entire unit which had mutinied, deserted, or shown dereliction of duty. One out of every ten men would be beaten to death, usually by the other nine, who would be forced to live outside the camp and in some instances obliged to renew the military oath, the sacramentum.
Factors in the legion's success
- As Montesquieu wrote, "[I]t should be noted that the main reason for the Romans becoming masters of the world was that, having fought successively against all peoples, they always gave up their own practices as soon as they found better ones."Examples of ideas that were copied and adapted include weapons like the gladius (Spanish Iberians) and warship design (Carthaginians), as well as military units such as heavy mounted cavalry and mounted archers (Persians).
- Roman organization was more flexible than those of many opponents. Over time, the legions effectively handled challenges ranging from cavalry, to guerrillas, to siege warfare.
- Roman discipline, organization and systematization sustained combat effectiveness over a longer period. These elements appear throughout the legion in training, logistics, field fortification etc.
- The Romans were more persistent and more willing to absorb and replace losses over time than their opponents. Wars with Carthage, the Parthians and barbarian forces illustrate this.
- Roman leadership was mixed, but over time it was often effective in securing Roman military success.
- The influence of Roman military and civic culture, as embodied particularly in the heavy infantry legion, gave the Roman military consistent motivation and cohesion.
- Strict, and more importantly, uniform discipline made commanding, maintaining, and replacing Roman legionaries a much more consistent exercise. Roman opponents tended to be tribal peoples without military science.
- Roman military equipment, particularly armour, was far more ubiquitous and heavy, especially in the late Republican / Early Imperial era, than that of most of their opponents. Soldiers equipped with shields, helmets and highly effective body armor had a major advantage over warriors protected, in many cases, with nothing other than their shields, particularly in a prolonged engagement.
- Roman engineering skills were second to none in the ancient world, and their mastery of both offensive and defensive siege warfare, specifically the construction and investiture of fortifications, was another major advantage for the Roman Legions.
- For a more detailed analysis, as well as the Romans in battle, see the articles Roman infantry tactics and Roman military personal equipment.
- Auxiliaries (Roman military)
- List of Roman wars
- List of Roman battles
- List of topics related to ancient Rome
- List of Roman legions
- List of Roman auxiliary regiments
- Military history of ancient Rome
- Structural history of the Roman military
- History of the Art of War. Vol 1. Ancient Warfare, Hans Delbrück
- Roman Warfare, Adrian Goldsworthy
- History of Warfare, John Keegan
- The Roman Army and Greece and Rome at War, Peter Connolly
- The Encyclopedia Of Military History: From 3500 B.C. To The Present. (2nd Revised Edition 1986), R. Ernest Dupuy, and Trevor N. Dupuy.
- War, Gwynne Dyer.
- The Evolution of Weapons and Warfare, Trevor N. Dupuy.
- Flavius Vegetius Renatus, De Re Militari (with English translation on-line)
- Julius Caesar, The Gallic War
- William Smith, D.C.L., LL.D.: A Dictionary of Greek and Roman Antiquities, John Murray, London, 1875.
- The Punic Wars, Adrian Goldsworthy.
- Carnage and Culture, Victor Davis Hanson
- The Fall of the Roman Empire: The Military Explanation, by Arther Ferrill, 1988
- The Complete Roman Army, by Adrian Goldsworthy
- The Military System Of The Romans, by Albert Harkness
- From the Rise of the Republic and the Might of the Empire to the Fall of the West, by Nigel Rodgers
- The Roman Army at War 100 BC - AD 200 (Oxford, September 1998) by Adrian Goldsworthy
- The Roman Military Museum with ancient military equipment
- The Roman Army Page, Gary Brueggeman (pop-up ads)
- UNRV's Roman Military
- Essays on life in the Late Roman Army, troop types etc by members of the Comitatus'' Reenactment and Living history group.
- The Roman Army at Roman-Empire.net
- Legio V Living History Group in Tennessee
legions in Tosk Albanian: Legion
legions in Slovak: Rímske vojsko
legions in Breton: Lejion roman
legions in Bulgarian: Легион
legions in Catalan: Legió romana
legions in Czech: Legie
legions in Welsh: Lleng Rufeinig
legions in Danish: Legion
legions in German: Römische Legion
legions in Estonian: Leegion
legions in Modern Greek (1453-): Λεγεώνα
legions in Spanish: Legión romana
legions in Esperanto: Legio
legions in French: Légion romaine
legions in Scottish Gaelic: Leigiun
legions in Galician: Lexión romana
legions in Korean: 로마 군단
legions in Italian: Legione romana
legions in Hebrew: לגיון
legions in Latin: Legio Romana
legions in Lithuanian: Legionas
legions in Hungarian: Légió
legions in Dutch: Legioen
legions in Japanese: ローマ軍団
legions in Norwegian: Romersk legion
legions in Polish: Legion
legions in Portuguese: Legião romana
legions in Russian: Римский легион
legions in Simple English: Roman legion
legions in Slovenian: Rimska legija
legions in Serbian: Римска легија
legions in Finnish: Legioona
legions in Swedish: Romersk legion
legions in Vietnamese: Lê dương La Mã
legions in Turkish: Roma lejyonu
legions in Ukrainian: Легіон
legions in Chinese: 罗马军团