Roman legion

Roman legion

Overview
A Roman legion normally indicates the basic ancient Roman army
Roman army
The Roman army is the generic term for the terrestrial armed forces deployed by the kingdom of Rome , the Roman Republic , the Roman Empire and its successor, the Byzantine empire...

 unit recruited specifically from Roman citizens. The organization of legions varied greatly over time but they were typically composed of perhaps 5,000 soldiers, divided into maniples and later into "cohorts
Cohort (military unit)
A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

". Maniples/Cohorts were divided into "centuries
Centuria
Centuria is a Latin substantive from the stem centum , denoting units consisting of 100 men. It also denotes a Roman unit of land area: 1 centuria = 100 heredia...

".

In reference to the early Kingdom of Rome (as opposed to the republic or empire) "the legion" means the entire Roman army
Army
An army An army An army (from Latin arma "arms, weapons" via Old French armée, "armed" (feminine), in the broadest sense, is the land-based military of a nation or state. It may also include other branches of the military such as the air force via means of aviation corps...

.

For most of the Roman Imperial period, the legions were a part of the Imperial army and formed its elite heavy infantry, recruited exclusively from Roman citizens (provincials who aspired to the citizenship
Roman citizenship
Citizenship in ancient Rome was a privileged political and legal status afforded to certain free-born individuals with respect to laws, property, and governance....

 gained it when honorably discharged from the auxiliaries).
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A Roman legion normally indicates the basic ancient Roman army
Roman army
The Roman army is the generic term for the terrestrial armed forces deployed by the kingdom of Rome , the Roman Republic , the Roman Empire and its successor, the Byzantine empire...

 unit recruited specifically from Roman citizens. The organization of legions varied greatly over time but they were typically composed of perhaps 5,000 soldiers, divided into maniples and later into "cohorts
Cohort (military unit)
A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

". Maniples/Cohorts were divided into "centuries
Centuria
Centuria is a Latin substantive from the stem centum , denoting units consisting of 100 men. It also denotes a Roman unit of land area: 1 centuria = 100 heredia...

".

In reference to the early Kingdom of Rome (as opposed to the republic or empire) "the legion" means the entire Roman army
Army
An army An army An army (from Latin arma "arms, weapons" via Old French armée, "armed" (feminine), in the broadest sense, is the land-based military of a nation or state. It may also include other branches of the military such as the air force via means of aviation corps...

.

For most of the Roman Imperial period, the legions were a part of the Imperial army and formed its elite heavy infantry, recruited exclusively from Roman citizens (provincials who aspired to the citizenship
Roman citizenship
Citizenship in ancient Rome was a privileged political and legal status afforded to certain free-born individuals with respect to laws, property, and governance....

 gained it when honorably discharged from the auxiliaries). A legion included a small cavalry attachment. The Roman army (for most of the Imperial period) consisted mostly of "auxiliary" cohorts who provided additional infantry, and the vast majority of the Roman army's cavalry.

Because of the enormous military successes of the Roman Republic
Roman Republic
The Roman Republic was the period of the ancient Roman civilization where the government operated as a republic. It began with the overthrow of the Roman monarchy, traditionally dated around 508 BC, and its replacement by a government headed by two consuls, elected annually by the citizens and...

 and the Roman Empire
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

, the legion has long been regarded as the prime ancient model for military efficiency and ability.

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.

Overview of typical organization & strength


Because legions were not standing units until the Marian reforms
Marian reforms
The Marian reforms of 107 BC were a group of military reforms initiated by Gaius Marius, a statesman and general of the Roman republic.- Roman army before 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.

A legion consisted of several cohort
Cohort (military unit)
A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

s of heavy infantry
Infantry
Infantrymen are soldiers who are specifically trained for the role of fighting on foot to engage the enemy face to face and have historically borne the brunt of the casualties of combat in wars. As the oldest branch of combat arms, they are the backbone of armies...

 known as legionaries. It was almost always accompanied by one or more attached units of auxiliaries
Auxiliaries (Roman military)
Auxiliaries formed the standing non-citizen corps of the Roman army of the Principate , alongside the citizen legions...

, who were not Roman citizens and provided cavalry
Cavalry
Cavalry or horsemen were soldiers or warriors who fought mounted on horseback. Cavalry were historically the third oldest and the most mobile of the combat arms...

, ranged troops and skirmisher
Skirmisher
Skirmishers are infantry or cavalry soldiers stationed ahead or alongside a larger body of friendly troops. They are usually placed in a skirmish line to harass the enemy.-Pre-modern:...

s to complement the legion's heavy infantry. The recruitment of non-citizens was rare but appears to have occurred in times of great need; For example Caesar appears to have recruited the Legio V Alaudae
Legio V Alaudae
Legio quinta Alaudae sometimes known as Gallica, was levied by Julius Caesar in 52 BC from native Gauls. Their emblem was an elephant, and their cognomen Alaudae came from the high crest on their helmets, typical of the Gauls, which made them look like larks...

 from non-citizen Gauls.

The size of a typical legion varied throughout the history of ancient Rome, with complements of 4,200 legionaries and 300 equites (drawn from the wealthier classes - in early Rome all troops provided their own equipment) in the republican period of Rome, (the infantry were split into 30 maniples
Maniple (military unit)
Maniple was a tactical unit of the Roman legion adopted from the Samnites during the Samnite Wars . It was also the name of the military insignia carried by such unit....

 of 120 legionaries each), to 5,200 men plus auxiliaries in the imperial period (split into 10 cohorts
Cohort (military unit)
A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

, 9 of 480 men each, plus the first cohort holding 800 men).

Roman kings (to c.500 BC)



In the period before the raising of the legio and the early years of the Roman Kingdom and the Republic, forces are described as being organized into centuries
Centuria
Centuria is a Latin substantive from the stem centum , denoting units consisting of 100 men. It also denotes a Roman unit of land area: 1 centuria = 100 heredia...

of roughly one hundred men. These centuries were grouped together as required and answered to the leader who had hired or raised them. Such independent organization persisted until the 2nd century BC amongst light infantry and cavalry, but was discarded completely in later periods with the supporting role taken instead by allied troops. The roles of century leader (later formalised as a centurion
Centurion
A centurion was a professional officer of the Roman army .Centurion may also refer to:-Military:* Centurion tank, British battle tank* HMS Centurion, name of several ships and a shore base of the British Royal Navy...

), second in command
Optio
An optio , sometimes anglicized option , was a soldier in the Roman army who held a position similar to that of an executive officer in modern armies...

 and standard bearer
Aquilifer
An aquilifer was a senior signifer bearing the eagle standard of a Roman legion. The name derives from the type of standard, aquila meaning "eagle", which was the universal type used since 104 BC. Before that time, the wolf, boar, bull and horse were also used...

 are referenced in this early period.

Much Roman history of the era is shrouded in legend but it is believed that during the reign of Servius Tullius
Servius Tullius
Servius Tullius was the legendary sixth king of ancient Rome, and the second of its Etruscan dynasty. He reigned 578-535 BC. Roman and Greek sources describe his servile origins and later marriage to a daughter of Lucius Tarquinius Priscus, Rome's first Etruscan king, who was assassinated in 579 BC...

, the census
Census
A census is the procedure of systematically acquiring and recording information about the members of a given population. It is a regularly occurring and official count of a particular population. The term is used mostly in connection with national population and housing censuses; other common...

 (from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

: censeō – accounting 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 their wealth and then organised into centuries as sub-units of the greater Roman army or legio (multitude). 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. These individuals would have had the most to lose should the state have fallen.

The first and wealthiest common class was armed in the fashion of the hoplite with spear, sword, helmet, breast plate and round shield (called clipeus
Clipeus
In the military of classical antiquity, a clipeus was a large shield worn by the Greeks and Romans as a piece of defensive armor, which they carried upon the arm, to secure them from the blows of their enemies...

in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

, similar to the Greek aspis
Aspis
"Aspis" is the generic term for the word shield. The aspis, which is carried by Greek infantry of various periods, is often referred to as a hoplon .According to Diodorus Siculus:-Construction:...

, also called hoplon); there were 82 centuries of these of which two were trumpeters. Roman soldiers had to purchase their own equipment. The second and third class also acted as spearmen but were less heavily armoured and carried a larger oval or rectangular shield. The fourth class could afford no armour; perhaps bearing a small shield and 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
Sling (weapon)
A sling is a projectile weapon typically used to throw a blunt projectile such as a stone or lead "sling-bullet". It is also known as the shepherd's sling....

. There were 32 centuries raised from this class, two of which were designated engineers. The army officers as well as the cavalry were drawn from leading citizens who enrolled as equestrians (equites). The equites were later placed in smaller groups of 30 that were commanded by decurions (which strangely means commander of ten). There were 18 centuries of equites.

Until the 4th century BC the massive Greek phalanx
Phalanx formation
The phalanx is a rectangular mass military formation, usually composed entirely of heavy infantry armed with spears, pikes, sarissas, or similar weapons...

 was the mode of battle. Roman soldiers would have thus looked much like Greek hoplite
Hoplite
A hoplite was a citizen-soldier of the Ancient Greek city-states. Hoplites were primarily armed as spearmen and fought in a phalanx formation. The word "hoplite" derives from "hoplon" , the type of the shield used by the soldiers, although, as a word, "hopla" could also denote weapons held or even...

s
. Tactics were no different from those of the early Greeks and battles were joined on a plain. Spearmen would deploy themselves in tightly packed rows to form a shield wall
Shield wall
The wall, is a military tactic that was common in many cultures in the Pre-Early Modern warfare age...

 with their spears pointing forwards. They charged the enemy supported by javelin throwers and slingers; the cavalry pursued the enemy, sometimes dismounting to support infantry in dire situations. The phalanx was a cumbersome military unit to manoeuvre and was easily defeated by mountain tribes such as the Volsci or Samnites in rough terrain.

Early civilian authorities called praetors
Praetor
Praetor was a title granted by the government of Ancient Rome to men acting in one of two official capacities: the commander of an army, usually in the field, or the named commander before mustering the army; and an elected magistratus assigned varied duties...

 doubled as military leaders during the summer war season. A declaration of war included a religious ceremony ending with 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
Roman Republic
The Roman Republic was the period of the ancient Roman civilization where the government operated as a republic. It began with the overthrow of the Roman monarchy, traditionally dated around 508 BC, and its replacement by a government headed by two consuls, elected annually by the citizens and...

 after the kings were overthrown, the legio was subdivided into two separate legions, each one ascribed to one of the two consul
Consul
Consul was the highest elected office of the Roman Republic and an appointive office under the Empire. The title was also used in other city states and also revived in modern states, notably in the First French Republic...

s. 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. Also, some warfare was still conducted by Roman forces outside the legionary structure, the most famous example being the campaign in 479 BC by the clan army of gens Fabia against the Etruscan city of Veii (in which the clan was annihilated). 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
    Cavalry
    Cavalry or horsemen were soldiers or warriors who fought mounted on horseback. Cavalry were historically the third oldest and the most mobile of the combat arms...

     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 lance
    Lance
    A Lance is a pole weapon or spear designed to be used by a mounted warrior. The lance is longer, stout and heavier than an infantry spear, and unsuited for throwing, or for rapid thrusting. Lances did not have tips designed to intentionally break off or bend, unlike many throwing weapons of the...

    s. 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 (turma
    Turma
    A turma was a cavalry squadron in the Roman army of the Republic and Empire. In the Byzantine Empire, it became applied to the larger, regiment-sized military-cum-administrative divisions of a thema....

    e
    ) of 30 men. These men were commanded by decurion
    Decurion (military)
    A decurion was a Roman cavalry officer in command of a squadron of cavalrymen in the Roman army.- Republican army :...

    s. 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
    Flanking maneuver
    In military tactics, a flanking maneuver, also called a flank attack, is an attack on the sides of an opposing force. If a flanking maneuver succeeds, the opposing force would be surrounded from two or more directions, which significantly reduces the maneuverability of the outflanked force and its...

     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 stirrup
    Stirrup
    A stirrup is a light frame or ring that holds the foot of a rider, attached to the saddle by a strap, often called a stirrup leather. Stirrups are usually paired and are used to aid in mounting and as a support while using a riding animal...

    s.

  • Velites
    Velites
    Velites were a class of infantry in the Polybian legions of the early Roman republic. Velites were light infantry and skirmishers who were armed with a number of light javelins, or hastae velitares, to fling at the enemy, and also carried short thrusting swords, or gladii for use in melee...

    (light infantry
    Light infantry
    Traditionally light infantry were soldiers whose job was to provide a skirmishing screen ahead of the main body of infantry, harassing and delaying the enemy advance. Light infantry was distinct from medium, heavy or line infantry. Heavy infantry were dedicated primarily to fighting in tight...

    ): The velites were mainly poorer citizens who could not 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
    Velites
    Velites were a class of infantry in the Polybian legions of the early Roman republic. Velites were light infantry and skirmishers who were armed with a number of light javelins, or hastae velitares, to fling at the enemy, and also carried short thrusting swords, or gladii for use in melee...

     were also used as scouts. They did not have a precise formal organization or formation.

  • Heavy infantry
    Heavy infantry
    Heavy infantry refers to heavily armed and armoured ground troops, as opposed to medium or light infantry, in which the warriors are relatively lightly armoured. As modern infantry troops usually define their subgroups differently , 'heavy infantry' almost always is used to describe pre-gunpowder...

    : 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
    Pilum
    The pilum was a javelin commonly used by the Roman army in ancient times. It was generally about two metres long overall, consisting of an iron shank about 7 mm in diameter and 60 cm long with pyramidal head...

    , a heavy javelin whose range was about 30 meters. After 387 BC, the preferred weapon for the hastati and principes was the gladius
    Gladius
    Gladius was the Latin word for sword, and is used to represent the primary sword of Ancient Roman soldiers. Early ancient Roman swords were similar to those used by the Greeks. From the 3rd century BC, the Romans adopted swords similar to those used by the Celtiberians and others during the early...

    , a short sword. Their hobnailed sandals (caligae
    Caligae
    Caligae are heavy-soled hob-nailed military boots worn by Roman legionary soldiers and auxiliaries throughout the Roman Republic and Empire. Worn by all ranks up to and including centurions, no other shoes in history stand as much symbol for the expansion of an empire than the famed caligae...

    ) were also an effective weapon against a fallen enemy (cf. the mediaeval misericorde). Prior to the Marian reforms (see below) the heavy infantry was subdivided, according to experience, into three separate lines of troops:
    • The hastati
      Hastati
      Hastatii were a class of infantry in the armies of the early Roman Republic who originally fought as spearmen, and later as swordsmen. They were originally some of the poorest men in the legion, and could afford only modest equipment — light armour and a large shield, in their service as the...

      (sing. hastatus) consisted of raw or inexperienced soldiers, considered to be less reliable than legionaries of several years' service.
    • The principes
      Principes
      Principes were spearmen, and later swordsmen, in the armies of the early Roman Republic. They were men in the prime of their lives who were fairly wealthy, and could afford decent equipment. They were the heavier infantry of the legion who carried large shields and wore good quality armour. Their...

      (sing. princeps) were men in their prime (late twenties to early thirties).
    • The triarii
      Triarii
      Triarii were one of the elements of the early Roman military Manipular legions of the early Roman Republic . They were the oldest and among the wealthiest men in the army, and could afford good quality equipment. They wore heavy metal armour and carried large shields, their usual position being...

      (sing. triarius) were the veteran soldiers, to be used in battle only in extreme situations (cf. the Imperial Guard of Napoleon I
      Napoleon I
      Napoleon Bonaparte was a French military and political leader during the latter stages of the French Revolution.As Napoleon I, he was Emperor of the French from 1804 to 1815...

       of France); they rested one knee down when not engaged in combat. The triarii served primarily as reserves or barrier troops
      Barrier troops
      Barrier troops, blocking units, or anti-retreat forces are formations of soldiers normally placed behind regular troops on a battle line to prevent panic or unauthorized withdrawal or retreat...

       designed to backstop the hastati and principes, and were equipped with long hastae
      Hasta (spear)
      Hasta is a Latin word meaning spear. Hastae were carried by early Roman Legionaries, in particular they were carried by and gave their name to those Roman soldiers known as Hastati...

      (spears) rather than the pilum and gladius (the hastati and principes stopped using spears in 387 BC). Thus armed, they fought in a phalanx formation
      Phalanx formation
      The phalanx is a rectangular mass military formation, usually composed entirely of heavy infantry armed with spears, pikes, sarissas, or similar weapons...

      . The sight of an advancing armored formation of triarii legionaries frequently discouraged exultant enemies in pursuit of retreating hastati and principes troops. Ad triarios redisse - To fall back upon the triarii was a Roman idiom
      Idiom
      Idiom is an expression, word, or phrase that has a figurative meaning that is comprehended in regard to a common use of that expression that is separate from the literal meaning or definition of the words of which it is made...

       – meaning to use one's last resort.


Each of these three lines was subdivided into (usually 10) chief tactical units called maniple
Maniple (military unit)
Maniple was a tactical unit of the Roman legion adopted from the Samnites during the Samnite Wars . It was also the name of the military insignia carried by such unit....

s. A maniple consisted of two centuries
Centuria
Centuria is a Latin substantive from the stem centum , denoting units consisting of 100 men. It also denotes a Roman unit of land area: 1 centuria = 100 heredia...

 and was commanded by the senior of the two centurion
Centurion
A centurion was a professional officer of the Roman army .Centurion may also refer to:-Military:* Centurion tank, British battle tank* HMS Centurion, name of several ships and a shore base of the British Royal Navy...

s. At this time, each century of hastati and principes consistd of 60 men; a century of triarii was 30 men. These 3000 men (twenty maniples of 120 men, and ten maniples of of 60 men), together with about 1200 velites and 300 cavalry gave the mid Republican ("manipular") legion a nominal strength of about 4500 men.

Late Republic (107-30 BC)



See also List of Roman legions for details of notable late Republican legions

See also Sub-Units of the Roman legion

The Marian reforms (of Gaius Marius) enlarged the centuries to 80 men, and grouped them into 6-century "cohorts" (rather than two-century maniples). Each century had its own standard and was made up of ten units (contubernia) of eight men who shared a tent, a millstone, a mule and cooking pot.

Following the reforms of the general Marius
Marius
Marius may refer to:* Marius , a male given name, a Roman family name, and a modern surname** Gaius Marius, Roman general and statesman.* Marius , on the Moon* Marius Hills, on the Moon* Marius , written by Marcel Pagnol...

 in 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
Gaius Marius
Gaius Marius was a Roman general and statesman. He was elected consul an unprecedented seven times during his career. He was also noted for his dramatic reforms of Roman armies, authorizing recruitment of landless citizens, eliminating the manipular military formations, and reorganizing the...

 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 the State of Rome itself. This development ultimately enabled Julius Caesar
Julius Caesar
Gaius Julius Caesar was a Roman general and statesman and a distinguished writer of Latin prose. He played a critical role in the gradual transformation of the Roman Republic into the Roman Empire....

 to cross the Rubicon
Rubicon
The Rubicon is a shallow river in northeastern Italy, about 80 kilometres long, running from the Apennine Mountains to the Adriatic Sea through the southern Emilia-Romagna region, between the towns of Rimini and Cesena. The Latin word rubico comes from the adjective "rubeus", meaning "red"...

 with an army loyal to him personally and effectively end the Republic.

The legions of the Late Republic and Early Empire are often called Marian legions. Following the Battle of Vercellae
Battle of Vercellae
The Battle of Vercellae, or Battle of the Raudine Plain, in 101 BC was the Roman victory of Consul Gaius Marius over the invading Germanic Cimbri tribe near the settlement of Vercellae in Cisalpine Gaul....

 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. At the same time, 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 (singular pilum
Pilum
The pilum was a javelin commonly used by the Roman army in ancient times. It was generally about two metres long overall, consisting of an iron shank about 7 mm in diameter and 60 cm long with pyramidal head...

), the short sword called gladius, chain mail (lorica hamata
Lorica hamata
The lorica hamata is a type of mail armour used by the Roman Republic and the Roman Empire. During the 1st century it was starting to be supplemented by lorica segmentata, but had been reintroduced as sole standard-issue armor by the 4th century. It was issued for both primary Legionary and...

), helmet and rectangular shield (scutum
Scutum (shield)
Scutum is the Latin word for "shield", although it has in modern times come to be specifically associated with the rectangular, semi-cylindrical body shield carried by Roman legionaries.-History:...

).

The role of allied legions would eventually be taken up by contingents of allied auxiliary troops, called Auxilia. Auxilia 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
Light infantry
Traditionally light infantry were soldiers whose job was to provide a skirmishing screen ahead of the main body of infantry, harassing and delaying the enemy advance. Light infantry was distinct from medium, heavy or line infantry. Heavy infantry were dedicated primarily to fighting in tight...

 or velites
Velites
Velites were a class of infantry in the Polybian legions of the early Roman republic. Velites were light infantry and skirmishers who were armed with a number of light javelins, or hastae velitares, to fling at the enemy, and also carried short thrusting swords, or gladii for use in melee...

, and labourers. There was also a reconnaissance
Reconnaissance
Reconnaissance is the military term for exploring beyond the area occupied by friendly forces to gain information about enemy forces or features of the environment....

 squad
Squad
In military terminology, a squad is a small military unit led by a non-commissioned officer that is subordinate to an infantry platoon. In countries following the British Army tradition this organization is referred to as a section...

 of 10 or more light mounted infantry
Mounted infantry
Mounted infantry were soldiers who rode horses instead of marching, but actually fought on foot . The original dragoons were essentially mounted infantry...

 called speculatores
Speculatores
Speculatores and Exploratores were the scouts and reconnaissance element of the Roman army.In both the legions and in the praetorian camp, speculatores were initially scouts but became bodyguards, couriers, law-enforcers, and sometimes executioners. Exploratores were tasked to keep watch on enemy...

who could also serve as messengers or even as an early form of military intelligence
Military intelligence
Military intelligence is a military discipline that exploits a number of information collection and analysis approaches to provide guidance and direction to commanders in support of their decisions....

 service.

As part of the Marian reforms, the legions' internal organization was standardized. Each legion was divided into cohorts
Cohort (military unit)
A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

. 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 centuries and in the case of the first cohort 12 centuries each led by a centurion assisted by an optio
Optio
An optio , sometimes anglicized option , was a soldier in the Roman army who held a position similar to that of an executive officer in modern armies...

. The cohorts came to form the basic tactical unit of the legions. Ranking within the legion was based on length of service, with the senior Centurion commanding the first century of the first cohort; he was called the primus pilus
Primus Pilus
The Primus pilus was the senior centurion of a Roman legion.-Historical role:In the late Roman republic, the cohort , became the basic tactical unit of the legions. The cohort was composed of five to eight centuries each led by a centurion assisted by an optio, a soldier who could read and write...

(First Spearmen), and reported directly to the superior officers (legates and tribuni). All career soldiers could be promoted to the higher ranks in recognition of exceptional acts of bravery or valour. A newly promoted junior Centurion would be assigned to the sixth century of the tenth cohort and slowly progressed through the ranks from there.

Every legion had a large baggage train which included 640 mules (1 mule for every 8 legionaries) only for the soldiers equipment. 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 cross stick to carry their loads on their shoulders. The soldiers were nicknamed Marius' Mules because of the amount of gear they had to carry themselves. This arrangement allowed for the possibility for the supply train to become temporarily detached from the main body of the legion, thus greatly increasing the army's speed when needed.

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
Julius Caesar
Gaius Julius Caesar was a Roman general and statesman and a distinguished writer of Latin prose. He played a critical role in the gradual transformation of the Roman Republic into the Roman Empire....

's legions during his campaign in Gaul often only had around 3,500 men.

Tactics were not very different from the past, but their effectiveness was largely improved because of 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. Governor
Roman governor
A Roman governor was an official either elected or appointed to be the chief administrator of Roman law throughout one or more of the many provinces constituting the Roman Empire...

s were not allowed to leave their provinces with their legions. When Julius Caesar
Julius Caesar
Gaius Julius Caesar was a Roman general and statesman and a distinguished writer of Latin prose. He played a critical role in the gradual transformation of the Roman Republic into the Roman Empire....

 broke this rule, leaving his province of Gaul and crossing the Rubicon
Rubicon
The Rubicon is a shallow river in northeastern Italy, about 80 kilometres long, running from the Apennine Mountains to the Adriatic Sea through the southern Emilia-Romagna region, between the towns of Rimini and Cesena. The Latin word rubico comes from the adjective "rubeus", meaning "red"...

 into Italy, he precipitated a constitutional crisis
Constitutional crisis
A constitutional crisis is a situation that the legal system's constitution or other basic principles of operation appear unable to resolve; it often results in a breakdown in the orderly operation of government...

. This crisis and the civil wars which followed brought an end to the Republic and led to the foundation of the Empire
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

 under Augustus
Augustus
Augustus ;23 September 63 BC – 19 August AD 14) is considered the first emperor of the Roman Empire, which he ruled alone from 27 BC until his death in 14 AD.The dates of his rule are contemporary dates; Augustus lived under two calendars, the Roman Republican until 45 BC, and the Julian...

 in 27 BC.

Early Empire (30 BC-AD 284)



See also Directory of Roman legions of the early Empire

See also Sub-Units of the Roman legion

Generals, during the recent Republican civil wars, had formed their own legions and numbered them as they wished. 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
Dux
Dux is Latin for leader and later for Duke and its variant forms ....

 and six duces). At the end of the civil war against Mark Antony
Mark Antony
Marcus Antonius , known in English as Mark Antony, was a Roman politician and general. As a military commander and administrator, he was an important supporter and loyal friend of his mother's cousin Julius Caesar...

, Augustus was left with around fifty legions, with several double counts (multiple Legio Xs for instance). For political and economic reasons, Augustus reduced the number of legions to 28 (which diminished to 25 after the Battle of Teutoburg Forest, in which 3 legions were slaughtered).

Beside streamlining the army Augustus also regulated the soldiers' pay. 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
Praetorian Guard
The Praetorian Guard was a force of bodyguards used by Roman Emperors. The title was already used during the Roman Republic for the guards of Roman generals, at least since the rise to prominence of the Scipio family around 275 BC...

 along with a permanent navy
Roman Navy
The Roman Navy comprised the naval forces of the Ancient Roman state. Although the navy was instrumental in the Roman conquest of the Mediterranean basin, it never enjoyed the prestige of the Roman legions...

 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 (hence the wry remark of the philosopher Favorinus
Favorinus
Favorinus of Arelata was a Roman sophist and philosopher who flourished during the reign of Hadrian.He was of Gaulish ancestry, born in Arelate . He is described as a hermaphrodite by birth...

 that It is ill arguing with the master of 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
Pax Romana
Pax Romana was the long period of relative peace and minimal expansion by military force experienced by the Roman Empire in the 1st and 2nd centuries AD. Since it was established by Caesar Augustus it is sometimes called Pax Augusta...

 probably ranged from 11,000 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
Division (military)
A division is a large military unit or formation usually consisting of between 10,000 and 20,000 soldiers. In most armies, a division is composed of several regiments or brigades, and in turn several divisions typically make up a corps...

.

Throughout the imperial
Roman Empire
The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

 era, the legions played an important political role. Their actions could secure the empire for a usurper
Roman usurper
Usurpers are individuals or groups of individuals who obtain and maintain the power or rights of another by force and without legal authority. Usurpation was endemic during roman imperial era, especially from the crisis of the third century onwards, when political instability became the rule.The...

 or take it away. For example, the defeat of Vitellius
Vitellius
Vitellius , was Roman Emperor for eight months, from 16 April to 22 December 69. Vitellius was acclaimed Emperor following the quick succession of the previous emperors Galba and Otho, in a year of civil war known as the Year of the Four Emperors...

 in the Year of the Four Emperors
Year of the Four Emperors
The Year of the Four Emperors was a year in the history of the Roman Empire, AD 69, in which four emperors ruled in a remarkable succession. These four emperors were Galba, Otho, Vitellius, and Vespasian....

 was decided when the Danubian
Danube
The Danube is a river in the Central Europe and the Europe's second longest river after the Volga. It is classified as an international waterway....

 legions chose to support Vespasian
Vespasian
Vespasian , was Roman Emperor from 69 AD to 79 AD. Vespasian was the founder of the Flavian dynasty, which ruled the Empire for a quarter century. Vespasian was descended from a family of equestrians, who rose into the senatorial rank under the Emperors of the Julio-Claudian dynasty...

.

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
Legatus
A legatus was a general in the Roman army, equivalent to a modern general officer. Being of senatorial rank, his immediate superior was the dux, and he outranked all military tribunes...

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)



See List of Roman legions for catalogue of late Empire legions


In the Later Roman Empire
Late Antiquity
Late Antiquity is a periodization used by historians to describe the time of transition from Classical Antiquity to the Middle Ages, in both mainland Europe and the Mediterranean world. Precise boundaries for the period are a matter of debate, but noted historian of the period Peter Brown proposed...

, the number of legions was increased and the Roman Army
Military establishment of the Roman empire
The principate of the Roman empire had no use for the republican army with its intense loyalties to competing generals. Beginning with the first emperor, Octavius Caesar, the principles totally replaced the citizen army with apparatus of professionals dedicated to carrying out the emperor's will in...

 expanded. There is no evidence to suggest that legions changed in form before the Tetrarchy
Tetrarchy
The term Tetrarchy describes any system of government where power is divided among four individuals, but usually refers to the tetrarchy instituted by Roman Emperor Diocletian in 293, marking the end of the Crisis of the Third Century and the recovery of the Roman Empire...

, 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
Diocletian
Diocletian |latinized]] upon his accession to Diocletian . c. 22 December 244  – 3 December 311), was a Roman Emperor from 284 to 305....

 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
Herculians
The Jovians and Herculians were the senior palatine imperial guard units of the Emperors of the late Roman Empire and the early Byzantine Empire from the 290s until the 7th century.-History:...

and Divitenses.

The 4th century saw a very large number of new, small legions created, a process which began under Constantine II
Constantine II (emperor)
Constantine II , was Roman Emperor from 337 to 340. Co-emperor alongside his brothers, his short reign saw the beginnings of conflict emerge between the sons of Constantine the Great, and his attempt to exert his perceived rights of primogeniture ended up causing his death in a failed invasion of...

. In addition to the elite palatini
Palatini (Roman military)
The palatini were elite regiments of the Late Roman army mostly attached to the comitatus praesentales, or imperial escort armies...

, other legions called comitatenses
Comitatenses
Comitatenses is the Latin plural of comitatensis, originally the adjective derived from comitatus , itself rooting in Comes .However, historically it became the accepted name for...

and pseudocomitatenses
Pseudocomitatenses
Pseudocomitatenses were a class of regiment in the Late Roman army. Although they were attached to the comitatus , they enjoyed lower status and pay to the comitatenses, the regular regiments of the comitatus...

, along with the auxilia palatina
Auxilia palatina
Auxilia palatina were infantry units of the Late Roman army, first raised by Constantine I as part of the new field army he created in about 325....

, provided the infantry of late Roman armies. The Notitia Dignitatum
Notitia Dignitatum
The Notitia Dignitatum is a unique document of the Roman imperial chanceries. One of the very few surviving documents of Roman government, it details the administrative organisation of the eastern and western empires, listing several thousand offices from the imperial court down to the provincial...

 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
Honorius (emperor)
Honorius , was Western Roman Emperor from 395 to 423. He was the younger son of emperor Theodosius I and his first wife Aelia Flaccilla, and brother of the eastern emperor Arcadius....

and Gratian
Gratian
Gratian was Roman Emperor from 375 to 383.The eldest son of Valentinian I, during his youth Gratian accompanied his father on several campaigns along the Rhine and Danube frontiers. Upon the death of Valentinian in 375, Gratian's brother Valentinian II was declared emperor by his father's soldiers...

enses
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 vexillatio
Vexillatio
A vexillatio was a detachment of a Roman legion formed as a temporary task force created by the Roman Army of the Principate. It was named from the standards carried by legionary detachments, vexillum , which bore the emblem and name of the parent legion...

nes
or from old legions. In addition there were 24 vexillationes palatini, 73 vexillationes comitatenses; 305 other units in the Eastern limitanei and 181 in the Western limitanei.

According to the late Roman writer Vegetius
Vegetius
Publius Flavius Vegetius Renatus, commonly referred to simply as Vegetius, was a writer of the Later Roman Empire. Nothing is known of his life or station beyond what he tells us in his two surviving works: Epitoma rei militaris , and the lesser-known Digesta Artis Mulomedicinae, a guide to...

' De Re Militari
De Re Militari
De Re Militari , also Epitoma Rei Militaris, is a treatise by the late Latin writer Vegetius about Roman warfare and military principles as a presentation of methods and practices in use during the height of Rome's power, and responsible for that power...

, each century had a ballista
Ballista
The ballista , plural ballistae, was an ancient missile weapon which launched a large projectile at a distant target....

 and each cohort had an onager
Onager (siege weapon)
The onager was a Roman siege engine, which derived its name from the kicking action of the machine, similar to that of an onager , it was created as a simpler, cheaper version of the ballista. The Onager is a type of catapult that uses torsional pressure, generally from twisted rope, to store...

, 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
Castra
The Latin word castra, with its singular castrum, was used by the ancient Romans to mean buildings or plots of land reserved to or constructed for use as a military defensive position. The word appears in both Oscan and Umbrian as well as in Latin. It may have descended from Indo-European to Italic...

) as well. They would even be employed on occasion, especially in the later Empire, as field artillery
Field artillery
Field artillery is a category of mobile artillery used to support armies in the field. These weapons are specialized for mobility, tactical proficiency, long range, short range and extremely long range target engagement....

 during battles or in support of river crossings.

Despite a number of reforms, the Legion system survived the fall of the Western Roman Empire
Western Roman Empire
The Western Roman Empire was the western half of the Roman Empire after its division by Diocletian in 285; the other half of the Roman Empire was the Eastern Roman Empire, commonly referred to today as the Byzantine Empire....

, and was continued in the Eastern Roman Empire until around 7th century, when reforms begun by Emperor Heraclius
Heraclius
Heraclius was Byzantine Emperor from 610 to 641.He was responsible for introducing Greek as the empire's official language. His rise to power began in 608, when he and his father, Heraclius the Elder, the exarch of Africa, successfully led a revolt against the unpopular usurper Phocas.Heraclius'...

 to counter the increasing need for soldiers around the Empire resulted in the Theme system. Despite this, the Eastern Roman/Byzantine armies continued to be influenced by the earlier Roman legions, and were maintained with similar level of discipline, strategic prowess, and organization.

Legionary ranks


Aside from the rank and file legionary (who received the base wage of 10 asses
As (coin)
The , also assarius was a bronze, and later copper, coin used during the Roman Republic and Roman Empire.- Republican era coinage :...

 a day or 225 denarii
Denarius
In the Roman currency system, the denarius was a small silver coin first minted in 211 BC. It was the most common coin produced for circulation but was slowly debased until its replacement by the antoninianus...

 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 (c. 290).

Senior officers

  • Legatus legionis
    Legatus legionis
    Legatus legionis was a title awarded to legion commanders in Ancient Rome.-History:By the time of the Roman Republic, the term legatus delegated authority...

    , Legate: The overall legion commander. The post was usually filled by a senator
    Roman Senate
    The Senate of the Roman Republic was a political institution in the ancient Roman Republic, however, it was not an elected body, but one whose members were appointed by the consuls, and later by the censors. After a magistrate served his term in office, it usually was followed with automatic...

    , 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
    Roman province
    In Ancient Rome, a province was the basic, and, until the Tetrarchy , largest territorial and administrative unit of the empire's territorial possessions outside of Italy...

     with only one legion, the legatus was also the provincial governor
    Roman governor
    A Roman governor was an official either elected or appointed to be the chief administrator of Roman law throughout one or more of the many provinces constituting the Roman Empire...

     and in provinces with multiple legions, each legion had a legatus and the provincial governor had overall command of them all.

  • Dux
    Dux
    Dux is Latin for leader and later for Duke and its variant forms ....

    , literally The Leader: A title not used until the later empire, or dominate
    Dominate
    The Dominate was the "despotic" latter phase of government in the ancient Roman Empire from the conclusion of the Third Century Crisis of 235–284 until the formal date of the collapse of the Western Empire in AD 476. It followed the period known as the Principate...

    , referring to a general in charge of two or more provincial military units. While the title of dux could refer to a Consul
    Consul
    Consul was the highest elected office of the Roman Republic and an appointive office under the Empire. The title was also used in other city states and also revived in modern states, notably in the First French Republic...

     or Imperator
    Imperator
    The Latin word Imperator was originally a title roughly equivalent to commander under the Roman Republic. Later it became a part of the titulature of the Roman Emperors as part of their cognomen. The English word emperor derives from imperator via Old French Empreur...

    , it usually referred to the commander-in-chief of the limitanei
    Limitanei
    The limitanei, meaning "the soldiers in frontier districts" The limitanei, meaning "the soldiers in frontier districts" The limitanei, meaning "the soldiers in frontier districts" (from the Latin phrase limes, denoting the military districts of the frontier provinces established in the late third...

     garrisoned within a province.

  • Tribunus laticlavius
    Military tribune
    A military tribune was an officer of the Roman army who ranked below the legate and above the centurion...

    , Broad Band Tribune: Named for the broad striped tunic 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. Because of 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
    Cursus honorum
    The cursus honorum was the sequential order of public offices held by aspiring politicians in both the Roman Republic and the early Empire. It was designed for men of senatorial rank. The cursus honorum comprised a mixture of military and political administration posts. Each office had a minimum...

    ).

  • Praefectus castrorum
    Prefect
    Prefect is a magisterial title of varying definition....

    , Camp Prefect: The Camp Prefect was third in command of the legion. Generally he was a long serving veteran from a lower social status than the tribunii whom he outranked, and who previously had served as primus pilus and finished his 25 years with the legions. He was used as a senior officer in charge of training a legion.

  • Tribuni angusticlavii
    Military tribune
    A military tribune was an officer of the Roman army who ranked below the legate and above the centurion...

    , Narrow Band Tribunes: Each legion had five more junior tribunes. They were normally young men of high birth who were not necessarily experienced. The more senior tribunus laticlavius rank existed to provide a more senior tribune to supervise these other tribunes.

Centurions



The rank of centurion
Centurion
A centurion was a professional officer of the Roman army .Centurion may also refer to:-Military:* Centurion tank, British battle tank* HMS Centurion, name of several ships and a shore base of the British Royal Navy...

 was an officer rank that included many grades, meaning centurions had very good prospects for promotion.
The most senior centurion
Centurion
A centurion was a professional officer of the Roman army .Centurion may also refer to:-Military:* Centurion tank, British battle tank* HMS Centurion, name of several ships and a shore base of the British Royal Navy...

 in a legion was known as the
primus pilus
Primus Pilus
The Primus pilus was the senior centurion of a Roman legion.-Historical role:In the late Roman republic, the cohort , became the basic tactical unit of the legions. The cohort was composed of five to eight centuries each led by a centurion assisted by an optio, a soldier who could read and write...

(first file or spear) who directly commanded the 1st century of the first cohort and commanded the whole first cohort when in battle. Within the second to tenth cohorts, the commander of each cohort's 1st century was known as a pilus prior and was in command of his entire respective cohort when in battle. The seniority of the pilus prior centurions was followed by the five other century commanders of the first cohort, who were known as primi ordines.

An ordinary centurion was the approximate equivalent of a Captain in a modern army, whereas the most senior centurion was closer to the equivalent of a full Colonel
Colonel
Colonel , abbreviated Col or COL, is a military rank of a senior commissioned officer. It or a corresponding rank exists in most armies and in many air forces; the naval equivalent rank is generally "Captain". It is also used in some police forces and other paramilitary rank structures...

.

The six centuries of a normal cohort
Cohort (military unit)
A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

, were, in order of precedence:
  • The forward hastati (forward spears)
  • The rear hastati (rear spears)
  • The forward principes (forward principal line)
  • The rear principes (rear principal line)
  • The forward triarii (forward third line)
  • The rear triarii (rear third line)


The centuries took their titles from the old use of the legion drawn up in three lines of battle using three classes of soldier. (Each century would then hole a cross-section of this theoretical line, although these century titles were now essentially nominal.) Each of the three lines is then sub-divided within the century into a more forward and a more rear century.
  • Primus pilus
    Primus Pilus
    The Primus pilus was the senior centurion of a Roman legion.-Historical role:In the late Roman republic, the cohort , became the basic tactical unit of the legions. The cohort was composed of five to eight centuries each led by a centurion assisted by an optio, a soldier who could read and write...

    , literally First File: The Primus Pilus was the commanding centurion of the first cohort and the senior centurion of the entire legion. He was called first file because he also directly commanded the 1st century of the first cohort. (Unlike other cohorts, the first cohort had only one javelin century, instead of a "front spear" and a "back spear" century). The Primus Pilus had a chance of later becoming a Praefectus Castrorum. When the primus pilus retired he would most likely gain entry into the equestrian class. He was paid 60 times the base wage.

  • Primi ordines: The "ranks of the first [cohort]" were 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.

  • Pilus prior: The "front file" centurions were the senior centurions of the cohorts. While the legion was in battle formation, the Pilus Prior was given command of the entire cohort. 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.

  • Other Centurion
    Centurion
    A centurion was a professional officer of the Roman army .Centurion may also refer to:-Military:* Centurion tank, British battle tank* HMS Centurion, name of several ships and a shore base of the British Royal Navy...

    s: 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 1st century of the first cohort was the highest, and the 6th century of the 10th cohort was the lowest. Paid ten times the basic wage.

Lower ranks

  • Optio
    Optio
    An optio , sometimes anglicized option , was a soldier in the Roman army who held a position similar to that of an executive officer in modern armies...

    : One for each centurion (59–60), they were appointed by the centurion from within the ranks to act as his second in command and were paid twice the basic wage. Equivalent to a modern Lieutenant
    Lieutenant
    A lieutenant is a junior commissioned officer in many nations' armed forces. Typically, the rank of lieutenant in naval usage, while still a junior officer rank, is senior to the army rank...

    .
  • Tesserarius
    Tesserarius
    A tesserarius , was a watch commander in the Roman army. They organized and had command over the nightly guard assigned to keep watch over the fort when in garrison or on campaign and were responsible for getting the watchwords from the commander and seeing that it was kept safe. There was one...

    : (Guard commander) One for each century. They acted as seconds to the Optios and were paid one and a half times the basic wage. Keeper of the watchword, administrative assistant to HQ Staff, third in command of a century. Equivalent to a modern First Sergeant
  • Decurio
    Decurion (military)
    A decurion was a Roman cavalry officer in command of a squadron of cavalrymen in the Roman army.- Republican army :...

    : Commanded a cavalry unit (turma
    Turma
    A turma was a cavalry squadron in the Roman army of the Republic and Empire. In the Byzantine Empire, it became applied to the larger, regiment-sized military-cum-administrative divisions of a thema....

    ) of 10 to 30 eques legionis.
  • Decanus
    Decanus
    Decanus means "chief of ten" in Late Latin. The term originated in the Roman army and became used thereafter for subaltern officials in the Byzantine Empire, as well as for various positions in the Church, whence derives the English title "dean"....

    : Commanded a contubernium
    Contubernium
    The contubernium was the smallest organized unit of soldiers in the Roman Army and was composed of eight legionaries. The men within the contubernium were known as contubernales. Ten contubernia were grouped into a centuria...

    or eight man tent party, equivalent to a Sergeant

Special duty posts

  • Aquilifer
    Aquilifer
    An aquilifer was a senior signifer bearing the eagle standard of a Roman legion. The name derives from the type of standard, aquila meaning "eagle", which was the universal type used since 104 BC. Before that time, the wolf, boar, bull and horse were also used...

    : A single position within the legion. The aquilifer was the legion's standard- or Aquila
    Aquila (Roman)
    The Aquila was the eagle standard of a Roman legion, carried by a special grade legionary known as an Aquilifer. One eagle standard was carried by each legion.-History:...

     (eagle)- bearer and was an enormously important and prestigious position. Losing the aquila was considered the greatest dishonor a legion could endure. 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
    Signifer
    A signifer was a standard bearer of the Roman legions. He carried a signum for a cohort or century. Each century had a signifer and within each cohort the first century's signifer would be the senior....

    : Each century had a signifer (thus, there were 59 in a legion) and within each cohort
    Cohort (military unit)
    A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

     the 1st century's signifer would be the senior. He was standard-bearer for the centurial signum, a spear shaft decorated with medallions and topped with an open hand to signify loyalty, which was a rallying point for the soldiers. In addition to carrying the signum, the signifer also assumed responsibility for the financial administration of the unit and functioned as the legionaries' banker. He was paid twice the basic wage.

  • Cornicen
    Cornicen
    A cornicen was a junior officer in the Roman Army. The cornicen's job was to signal salutes to officers and sound orders to the legions. The cornicines played the cornu . Cornicines always marched at the head of the centuries, with the tesserary and the signifer...

    (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. He was paid twice the basic wage.

  • Imaginifer
    Imaginifer
    The imaginifer was one of the signiferi in a legion in the times of the Roman Empire, who carried the imago - the image - of the emperor. The imaginifer was added to the ranks of the legions when the Imperial Cult was first established during the reign of Augustus. The imago was a three...

    : A special position from the time of Augustus
    Augustus
    Augustus ;23 September 63 BC – 19 August AD 14) is considered the first emperor of the Roman Empire, which he ruled alone from 27 BC until his death in 14 AD.The dates of his rule are contemporary dates; Augustus lived under two calendars, the Roman Republican until 45 BC, and the Julian...

     onwards. Carried the standard bearing the image of the Emperor as a constant reminder of the troops' loyalty to him. He was paid twice the basic wage.

  • Immunes
    Immunes
    Ancient Rome's military was highly advanced for its time, divided into multiple units to maximize efficiency and power. One such unit was the immune class. By definition, the immunes were legionary soldiers who possessed specialized skills, qualifying them to perform duties atypical of a Roman...

    : Immunes were legionary soldiers who possessed specialized skills, qualifying them for better pay and excusing them from labour and guard work. Engineer
    Engineer
    An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...

    s, artillerymen, musician
    Musician
    A musician is an artist who plays a musical instrument. It may or may not be the person's profession. Musicians can be classified by their roles in performing music and writing music.Also....* A person who makes music a profession....

    s, drill and weapons instructors, carpenter
    Carpenter
    A carpenter is a skilled craftsperson who works with timber to construct, install and maintain buildings, furniture, and other objects. The work, known as carpentry, may involve manual labor and work outdoors....

    s, hunters, medical staff and military police
    Military police
    Military police are police organisations connected with, or part of, the military of a state. The word can have different meanings in different countries, and may refer to:...

     were all immune soldiers. These men were still fully trained legionaries however and were called upon to serve in the battle lines when needed.

  • Evocati
    Evocatus
    Evocatus was the Latin term for a soldier in the Roman army who had served out his time and obtained a discharge but had voluntarily enlisted again at the invitation of the consul or other commander....

    : Veterans of the Roman army who had the right to retire, but had chosen to stay on after their tenure
    Tenure
    Tenure commonly refers to life tenure in a job and specifically to a senior academic's contractual right not to have his or her position terminated without just cause.-19th century:...

     was finished. During this period they received double pay and were excluded from regular duties such as manual labour.

  • Duplicarius
    Duplicarius
    A duplicary was a pay grade in the Roman Army receiving double the basic pay. The grade could also be awarded to ordinary legionary soldiers, regardless of rank, as a reward for outstanding bravery or service....

    : A special pay grade that could also be awarded regardless of rank, received double the basic pay.

Pay


From the time of Gaius Marius
Gaius Marius
Gaius Marius was a Roman general and statesman. He was elected consul an unprecedented seven times during his career. He was also noted for his dramatic reforms of Roman armies, authorizing recruitment of landless citizens, eliminating the manipular military formations, and reorganizing the...

 onwards, legionaries received 225 denarii
Denarius
In the Roman currency system, the denarius was a small silver coin first minted in 211 BC. It was the most common coin produced for circulation but was slowly debased until its replacement by the antoninianus...

a year (equal to 900 Sestertii
Sestertius
The sestertius, or sesterce, was an ancient Roman coin. During the Roman Republic it was a small, silver coin issued only on rare occasions...

); this basic rate remained unchanged until Domitian
Domitian
Domitian was Roman Emperor from 81 to 96. Domitian was the third and last emperor of the Flavian dynasty.Domitian's youth and early career were largely spent in the shadow of his brother Titus, who gained military renown during the First Jewish-Roman War...

, 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
Septimius Severus
Septimius Severus , also known as Severus, was Roman Emperor from 193 to 211. Severus was born in Leptis Magna in the province of Africa. As a young man he advanced through the customary succession of offices under the reigns of Marcus Aurelius and Commodus. Severus seized power after the death of...

, who increased it to 500 denarii a year. However, the soldiers did not receive all the money in cash, as the state deducted their pay with a clothing and food tax. To this wage, a legionary on active campaign would hope to add the booty of war, from the bodies of their enemies and as plunder from enemy settlements. Slaves could also be claimed from the prisoners of war and divided amongst the legion for later selling, which would bring in a sizeable supplement to their regular pay.

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
Augustus
Augustus ;23 September 63 BC – 19 August AD 14) is considered the first emperor of the Roman Empire, which he ruled alone from 27 BC until his death in 14 AD.The dates of his rule are contemporary dates; Augustus lived under two calendars, the Roman Republican until 45 BC, and the Julian...

 and/or a plot of good farmland (good land was in much demand); farmland given to veterans often helped in establishing control of the frontier regions and over rebellious provinces. Later, under Caracalla
Caracalla
Caracalla , was Roman emperor from 198 to 217. The eldest son of Septimius Severus, he ruled jointly with his younger brother Geta until he murdered the latter in 211...

, the praemia increased to 5000 denarii.

Symbols


From 104 BC onwards, each legion used an aquila
Aquila (Roman)
The Aquila was the eagle standard of a Roman legion, carried by a special grade legionary known as an Aquilifer. One eagle standard was carried by each legion.-History:...

 (eagle) as its standard symbol. The symbol was carried by an officer known as aquilifer
Aquilifer
An aquilifer was a senior signifer bearing the eagle standard of a Roman legion. The name derives from the type of standard, aquila meaning "eagle", which was the universal type used since 104 BC. Before that time, the wolf, boar, bull and horse were also used...

, and its loss was considered to be a very serious embarrassment, and often led to the disbanding of the legion itself. Normally this was because any legion incapable of regaining its eagle in battle was so severely mauled it was no longer combat effective.

In Gallic War (Bk IV, Para. 25), Julius Caesar describes an incident at the start of his first invasion of Britain in 55 BC 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
Legio X Gemina
Legio decima Gemina , was one of the four legions used by Julius Caesar in 58 BC, for his invasion of Gaul. There are still records of the X Gemina in Vienna in the beginning of the 5th century. The legion symbol was a bull...

 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
Imaginifer
The imaginifer was one of the signiferi in a legion in the times of the Roman Empire, who carried the imago - the image - of the emperor. The imaginifer was added to the ranks of the legions when the Imperial Cult was first established during the reign of Augustus. The imago was a three...

, whose role was to carry a pike with the imago (image, sculpture) of the emperor as pontifex maximus
Pontifex Maximus
The Pontifex Maximus was the high priest of the College of Pontiffs in ancient Rome. This was the most important position in the ancient Roman religion, open only to patricians until 254 BC, when a plebeian first occupied this post...

.

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, vexillatio
Vexillatio
A vexillatio was a detachment of a Roman legion formed as a temporary task force created by the Roman Army of the Principate. It was named from the standards carried by legionary detachments, vexillum , which bore the emblem and name of the parent legion...

nes
. 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. This was considered a great honour and would bring the recipient much prestige.

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
Disciplina
In Roman mythology, Disciplina was a minor deity and the personification of discipline. The word disciplina itself, a Latin noun, is multi-faceted in meaning; it refers to education and training, self-control and determination, knowledge in a field of study, and an orderly way of life. The goddess...

, 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 (Tac. Annals I, 23)
  • Reduction of rations or to be forced to eat barley instead of the usual grain ration
  • Pecuniaria 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 by 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

Major punishments

  • Fustuarium
    Fustuarium
    In the military of ancient Rome, fustuarium or fustuarium supplicium was a severe form of military discipline in which a soldier was cudgeled to death...

    — 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
    Decimation (Roman Army)
    Decimation |ten]]") was a form of military discipline used by officers in the Roman Army to punish mutinous or cowardly soldiers. The word decimation is derived from Latin meaning "removal of a tenth".-Procedure:...

    — a sentence carried out against an entire unit which had mutinied, deserted, or shown dereliction of duty. One out of every ten men, chosen by lots, would be beaten to death, usually by the other nine with their bare hands, 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
Gladius
Gladius was the Latin word for sword, and is used to represent the primary sword of Ancient Roman soldiers. Early ancient Roman swords were similar to those used by the Greeks. From the 3rd century BC, the Romans adopted swords similar to those used by the Celtiberians and others during the early...

 (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 most notably, the campaigns against Pyrrhus of Epirus
    Pyrrhus of Epirus
    Pyrrhus or Pyrrhos was a Greek general and statesman of the Hellenistic era. He was king of the Greek tribe of Molossians, of the royal Aeacid house , and later he became king of Epirus and Macedon . He was one of the strongest opponents of early Rome...

    , 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 military equipment, particularly armour, was thicker and far more ubiquitous, 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 ancient Europe, 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.

See also



  • Roman army
    Roman army
    The Roman army is the generic term for the terrestrial armed forces deployed by the kingdom of Rome , the Roman Republic , the Roman Empire and its successor, the Byzantine empire...

  • Early Roman army
    Early Roman army
    The Early Roman army refers to the army deployed by ancient Rome during its Regal Era and its early Republic, until ca. 300 BC, when the so-called "Polybian" or manipular legion was introduced....

  • Roman army of the mid-Republic
    Roman army of the mid-Republic
    The Roman army of the mid-Republic , refers to the armed forces deployed by the mid- Roman Republic The Roman army of the mid-Republic (also known as the manipular Roman army or the "Polybian army"), refers to the armed forces deployed by the mid- Roman Republic The Roman army of the mid-Republic...

  • Marian Roman army
  • Imperial Roman army
    Imperial Roman army
    The Imperial Roman army refers to the armed forces deployed by the Roman Empire during the Principate era .Under the founder–emperor Augustus , the legions, which were formations numbering about 5,000 heavy infantry recruited from Roman citizens only, were transformed from a mixed conscript and...

  • Late Roman army
    Late Roman army
    The Late Roman army is the term used to denote the military forces of the Roman Empire from the accession of Emperor Diocletian in 284 until the Empire's definitive division into Eastern and Western halves in 395. A few decades afterwards, the Western army disintegrated as the Western empire...

  • Auxiliaries (Roman military)
    Auxiliaries (Roman military)
    Auxiliaries formed the standing non-citizen corps of the Roman army of the Principate , alongside the citizen legions...

  • 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
    Military history of ancient Rome
    From its origin as a city-state in Italy in the 8th century BC, to its rise as an empire covering much of Southern Europe, Western Europe, Near East and North Africa and fall in the 5th century AD, the political history of Ancient Rome was typically closely entwined with its military history...

  • Structural history of the Roman military
    Structural history of the Roman military
    The structural history of the Roman military concerns the major transformations in the organization and constitution of ancient Rome's armed forces, "the most effective and long-lived military institution known to history." From its origins around 800 BC to its final dissolution in AD 476...

  • For a more detailed analysis, as well as the Romans in battle, see the articles Roman infantry tactics
    Roman infantry tactics
    Roman infantry tactics refers to the theoretical and historical deployment, formation and maneuvers of the Roman infantry from the start of the Roman Republic to the fall of the Western Roman Empire. The article first presents a short overview of Roman training. Roman performance against different...

     and Roman military personal equipment.

External links