Roman legion

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'' 'Legion' redirects here. For other uses of this word, see: Legion (disambiguation).

A modern reconstruction of a Roman centurion around AD 70

The Roman legion (from Latin legio, legionis, f., from lego, legere, legi, lectus — "to collect") was the basic military unit of the ancient Roman army. It consisted of a core of heavy infantry (legionaries), with auxiliary cavalry and ranged troops, typically skirmishers. The size of a typical legion varied widely throughout the history of ancient Rome, with complements ranging from 5000-6000 men in the republican period of Rome, to the fairly standard number of around 5,400 in the early and middle imperial period and finally to on average 1000-2000 men in the very late imperial period. 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 Roman Empire, there were usually about 28 standing Legions plus their Auxiliaries, with more raised as needed or as able.

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.

Contents

History

Early history

Originally, in the time of the Kings, the legio ("conscription") was the whole Roman army, composed of levied citizens. Much of Roman history of this era is founded on legends, but it is believed that during the reign of Servius Tullius, all Roman able-bodied, property-owning male citizens were first divided into five classes for military service based on wealth, since soldiers provided their own weapons and equipment. These classes were further organized into units of 100 called Centuries.

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 in raids, it is uncertain if the full manpower of the legions was summoned at one time. Legions become organized in a more formal way 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 army (two per consul), other units were levied by campaign. Rome's Italian allies were required to provide a legion to support each Roman legion.

Mid-Republic

The military tribunes appeared after 331 BC (at first these tribunes took turns as the legion's commanding officer). The internal organization of the legion became more sophisticated, from the classic phalanx to the manipular system, and allowed important tactical innovations. For the first time, the classes of soldiers who comprised the legions was based on experience and age rather than wealth, with standard weapons and equipment issued by the state. (The exception was the Equites, who comprised the cavalry elements and still provided their own horses).

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 upstarts 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 javelins. The cavalry was outnumbered in the legion. In a total of circa 3000 men, the legion had only around 300 horsemen, divided into 10 units of 30 men. These men were commanded by decurions. Allied legions were required to have 600 horsemen. 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;

Velites (light infantry): The velites were basically javelin throwers who did not have a precise formal organization or function in battle, being used where there was need for them. Normally they would deploy in front of the legion and try to break up the enemy formation, though this rarely accomplished much. After throwing their javelins they would retreat through the gaps between the maniples;

Heavy 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 short spear (pilum). The preferred weapon was the gladius, a short sword. The heavy infantry was subdivided, according to the legionaries' experience in the Republican Legion prior to the Marian reforms, which abolished the separate classes of troops turning the legion into a professional force, into three separate lines:
* The hastati (sing. hastatus) were the younger ones and formed the front line
* The principes (sing. princeps), men in their prime ages (late twenties to early thirties), composed the second line of the legion
* The triarii (sing. triarius) were the veteran soldiers that occupied the rear; only in extreme situations would they be used in battle. They were equipped with spears rather than the pilum and gladius.

Each of these three lines was subdivided into maniples, the lowest subunit of the army, each consisting of two centuries commanded by the senior of the two centurions. Centuries were nominally 80 soldiers each (not 100, as is popularly believed), but in practice might be as few as 60, especially in the less numerous triarii maniples. 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.

During deployment, the maniples were commonly arranged in a chequered formation called quincunx. However, it is unlikely that they entered battle in this way. Principes maniples would cover the open space left by the hastati, and be covered in return by triarii maniples. The two centuries of each maniple were formed up one behind the other. After the velites had retreated through the 'Hastati', the 'posterior' century would march to the left and then forward so that they presented a solid line. Then the Hastati would charge. If they were losing the fight, the 'posterior' century returned to its position creating gaps again. Then the maniples would fall back through the gaps in the 'Principes', who followed the same procedure to form a battle line and charge. If the Principes could not break the enemy, they would retreat behind the 'Triarii' and the whole army would leave the battlefield in good order. This is only standard procedure and was often modified; at Zama, Scipio deployed his entire legion in a single line to envelop Hannibal's army just as Hannibal had done at Cannae.

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Marian reforms

Previously ephemeral in form, at the end of the 2nd century BC Marius reformed the legions to be a professional force drawing from the poorest classes, enabling Rome to field larger armies and providing employment for jobless citizens. However this put the loyalty of the soldiers in the hands of their general rather than Rome itself, and after several civil wars the Republic was abolished.

The Cohort legions of the late republic and early empire are often called Marian legions. Following the Battle of Vercellae in 101 B.C. Marius granted all Italian soldiers Roman citizenship. He justified this action to the Senate by saying 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. Thus the three different types of heavy infantry were replaced by a single, standard type of Legionary based on the Principes

The role of allied legions would eventually be taken up by contingents of allied/auxiliary troops, called Auxilia. Each Legion had a same size or near same size Auxilia (auxiliary), which contained specialist units, engineers and pioneers, artillerymen and siege craftsmen, service and support units plus units made up of non-citizens (who were granted Roman citizenship upon discharge) and undesirables. These were usually formed into complete units such as light cavalry, light infantry or velites, and laborers. 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.

During these reforms, the Legions were also organized into permanent cohorts for the first time. Prior to this cohorts had been temporary administrative units or tactical task forces of several maniples, even more transitory than that of the legions of the early republic themselves. Now the cohorts were six to ten permanent units, composed of five to eight 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.

Every legion had a baggage train of 500–550 mules, or about 1 mule for every 10 legionaries. To keep these baggage trains from becoming too large, Marius had each man carry as much of his own equipment as he could, including his own armour, weapons and 15 days' rations or about 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.

A typical legion of this period had around 4,000–5,000 legionaries as well as a large number of camp followers, servants and slaves. Legions could contain as many as 6,000 fighting men divided among several cohorts, although later in Roman history the number was reduced to 1,000 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.

Late Republic and early Empire

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 could not 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.

For political and economic reasons, Augustus reduced the number of legions from nearly 50 to only 25. 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 X's for instance). As well as streamlining the army and regulating the soldiers' pay, he corrected this numbering anomaly. During this time, there was a high incidence of Gemina (twins) legions, where two legions were consolidated into a single organization.

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.

High empire

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 4,000–6000 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 8,000–12,000 (With the more prestigious legions and those stationed on hostile borders or in restive provinces tending to be larger). Some legions may have even been reinforced at times with units making the associated force near 15–16,000 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 an Imperial hopeful or take it away. An example is the defeat of Vitellius in the Year of the Four Emperors, decided in the moment that 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 legate or legatus. 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 and the praefectus castrorum (commander of the camp) as well as other specialists such as priests and musicians.

Locations of the Roman legions in AD 80

Locations of Roman legions, AD 80.

This listThe list is taken, with modifications, from: Simkins, Michael, The Roman Army from Caesar to Trajan [Rev ed.], Osprey Publishing, 1984. ISBN 0850455286. shows the locations of the Roman legions around AD 80:

Legio IX Hispana: York
Legio XX Valeria Victrix and Legio II Adiutrix: Chester
Legio II Augusta: Caerleon
Legio XXII Primigenia and Legio X Gemina: Nijmegen
Legio VI Victrix: Neuss
Legio XXI Rapax: Bonn
Legio XIV Gemina: Mainz
Legio I Adiutrix: near Mainz
Legio VIII Augusta: Strasbourg
Legio XI Claudia: Vindonissa
Legio XV Apollinaris: Carnuntum
Legio XIII Gemina: Poetovio
Legio VII Claudia: Viminacium
Legio V Macedonica: Oescus (modern Gigen)
Legio I Italica: Novae (modern Svishtov)
Legio V Alaudae: near Danube
Legio IV Flavia Felix: Burnum
Legio XVI Flavia Firma: Satala
Legio XII Fulminata: Melitene
Legio VI Ferrata: Samosata
Legio IV Scythica: Zeugma
Legio III Gallica: near Damascus
Legio X Fretensis: Jerusalem
Legio XXII Deiotariana: Nicopolis
Legio III Cyrenaica: Coptos
Legio III Augusta: Lambaesis
Legio VII Gemina: Leon

Late Empire

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. 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 armiesTotals from summary of Notitia Dignitatum in Richardot, Philippe, La fin de l'armée romaine 284-476 [3rd ed.] Economica, 2005. ISBN 2717848614.. 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 Vexillations 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 (or Wild Ass in Latin), 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 officers

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).

Senior officers

Dux: A general in charge of two or more legions. While the title of dux could refer to a Consul or Imperator, it usually refers to the Roman Governor of the provinces. As the Governor, the Dux was both the highest civil official as well as the commander-in-chief of the legions garrisoned within the province. This office was similar to the modern Major General.

Legatus legionis: The overall legionary commander. This post was generally appointed by the emperor to a man who was usually a former Tribunus Laticlavius and held command for 3 or 4 years, although 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. This office was similar to the modern Brigadier General.

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. This office was similar to the modern Colonel.

Praefectus Castrorum: The camp Prefect. Generally he was a long serving veteran who had been promoted through the ranks of the centurions and was 3rd in overall command. This rank was similar to the modern Lieutenant Colonel.

Tribuni Angusticlavii: Each legion had five military tribunes of equestrian (knight) class citizens. They were in many cases career officers and served many of the important administrative tasks of the Legion, but still served in a full tactical command function during engagements. This rank was similar to the modern Major.

Primus Pilus: The "First File" or "first spearman" was the commanding centurion of the first cohort and the senior centurion of the entire Legion. When the Primus Pilus retired he was guaranteed entry into the Equestrian Class. He was paid 60 times the base wage. This rank was similar to a modern Captain, but of the highest degree.

Mid-level officers

Centurions: 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 as well as issuing 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 Century 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). This rank is compared to the modern Captain.

Primi Ordines: 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 similar to the modern Captain, but senior to all other Centurions, save the Primus Pilus and Pilus Prior.

The Pilus Prior: The ten Centurions of the First Centuires 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, only the most senior of all the Centurions within the Legions. These positions were usually held by experienced veteran soldiers who had been moved up within the ranks. This rank is similar to the modern Captain, but subordinate to the Primus Pilus.

Low-level officers

Optio: One for each Centurion (59), they were appointed by the Centurion from within the ranks to act as his second in command. Paid twice the basic wage. This rank is similar to the modern First Lieutenant.

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. This rank is similar to the modern Second Lieutenant.

Decurion: Led a Contubernium, or "Tent Group", of 8 to 10 men. Each Century had 8 to 10 of these. Paid one and a quarter times basic wage. This rank is similar to the non-commissioned officer Sergeant.

Special officers

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 dishonor. The next step up would be in a post as a Centurion. 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 troop's loyalty to him.

Symbols

From 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.

In 'The 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.

Life in the legions

Discipline

The 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.

Minor punishments

Castigatio: being hit by the centurion with his staff or animadversio fustium
Reduction of rations, or to be forced to eat barley instead of the usual grain ration
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.
Pecunaria multa: fines or deductions from the pay allowance

Major punishments

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 put to death. The rest of the men would be forced to live outside the camp and in some instances obliged to renew the military oath, the sacramentum.

Bibliography

''History of the Art of War. Vol 1. Ancient Warfare, Hans Delbrück
Roman Warfare, Adrian Goldsworthy
History of Warfare, John Keegan
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)
Gaius Julius Caesar, The Gallic War
William Smith, D.C.L., LL.D.: A Dictionary of Greek and Roman Antiquities, John Murray, London, 1875.

Notes

External links

[The Roman Military Museum with ancient military equipment]
[The Roman Army Page], Gary Brueggeman (pop-up ads)
[UNRV's Roman Military]