A Short History of the Roman Legion from the Republic to the Imperial Era Content from the guide to life, the universe and everything

A Short History of the Roman Legion from the Republic to the Imperial Era

0 Conversations

The Roman Military Machine
The Roman Legion | The Gladiators of Rome
The Groma: The Tool That Built An Empire
Ranks in the Roman Military | The Fleets Roman Of The Roman Empire
Roman Navy Ranks | The Ships of the Roman Fleet | Roman Fleet Types and Patrol Areas
A Roman Mystery - The Lost 9th Legion | The Roman Conquest of Britain
The Naval and Coastal Defences of Roman Britain (The Classis Britannica) | The Provinces Of Roman Britain
Roman soldiers.

The Legion was the basic fighting unit of Ancient Rome, and was an extremely effective fighting force that enabled the Romans to conquer a huge part of the then known world. The Romans created an empire stretching from Britain to the borders of the Parthian and the Sassanid empires in what is now eastern Turkey. They left Europe with a rich legacy from writing to democracy.

The first Legions were formed in the 8th Century BC. They reformed into a permanent standing army in 107 BC during the Roman Republic. The Legions continued to expand and defend the Empire until the fall of the Western Empire around 476 AD.

After the sack of Rome the Eastern Empire with its capital at Byzantium (also known as Constantinople and now Istanbul) survived for another thousand years. The Legions continued to defend them; isolated from the West they eventually became a mercenary force with few Romans in their ranks. They continued to defend the Eastern Empire until its fall in 1453 AD.

The Then 'Known World'

Alexander the Great had discovered much of the world to the Mediterranean's east so the Romans who admired him would also have known of those lands. The Romans would have had a knowledge of the Chinese and Indian civilisations as well as their close neighbours in Greece, Egypt and the Middle East. Through trade the Romans gained considerable knowledge of the existence of other civilisations, such as China and Korea which supplied silks. The people living in a large section of Africa south of the Sahara were known because they supplied elephants and lions for use in arenas around the Empire, including the most famous, the Flavian Amphitheatre, known as the Colosseum to tourists. By the time of Emperor Augustus, merchant ships were crossing the Indian Ocean to trade with India for exotic goods and tigers.

From a Kingdom to a Republic

The kingdom of Rome was founded during the 8th Century BC and the origin of the Roman Army can be traced to these early days when elected kings ruled Rome. In 509 BC, the last king Lucius Tarquinius Superbus, was overthrown. From then on Rome, and the lands it had conquered, was ruled by the Senate. When the Senate needed an army it conscripted or 'levied' one or more Legions from the property owning classes. This service was a duty, an obligation by law to perform military service as required. As the Latin for levy is legio, this gave the units of the Roman Army the name Legion. The early senatorial Legions were smaller than those of the Imperial period, having an average strength of 3,000 men compared to around 5,000 later on. Fortunately for this citizen army, a normal campaigning season was short; if a campaign took place over a long period, a new Legion was often called up and sent to take over from the serving one. All Legions were disbanded when they were no longer required.

The problem with this system was that the further away they travelled from home, the less effective they became.

Early Roman Battle Tactics

During the senatorial era, two basic fighting systems were developed: the Camillan and later the Polybian.

Camillan System

In the 4th Century BC a system known as the Camillan was in use. At this time Rome had a tribal culture, consisting of 4 Urban Tribes and 31 Rural Tribes1. The forces of Rome were organised by social rank and tribal affiliation, and fought mainly with spears, using swords in close combat. This was all very heroic and possibly influenced by Trojan tactics, or the Greek tactics used at Troy - one of the foundation myths of Rome states that Aeneas, Prince of Troy, settled in the south of Rome after defeating King Turnus in battle. Many myths contain elements of truth, and if Rome had indeed been colonised by experienced Trojan warriors, this could provide a possible explanation for the origin of Rome's tactical superiority on the battlefield.

Polybian Tactics

As Rome started to expand, men were recruited from the new provinces so that by the 3rd Century BC, the tribal influences upon the military had become less important. A new fighting system known as the Polybian was introduced. Unlike the Camillan system, this system required all infantrymen to carry two of the newly introduced throwing spears. The throwing spear (pilum) was designed to pierce the enemy's shields. The untempered iron shaft would then bend, making the shield unusable. As it is a lot easier to kill a shieldless opponent, this would give the Romans a tactical advantage. Once the pilum had been thrown the men fought with swords. This was the system that developed over time into the legionary battle tactics. Publius Cornelius Scipio Africanus, best known as Scipio, is the general who stands out from this period. He was a strong influence on the development of the Imperial battle tactics.

Marius' Mules

When Rome had expanded to the point that a full-time standing army became essential, Gaius Marius a Roman general and statesman, introduced reforms in the Senate and created laws that in 107 BC, allowed the forming of a permanent standing army2. His reforms also increased the amount of equipment the men of the Legion had to carry. Due to this burden the men of the Legions acquired the nickname muli mariani or 'Marius' Mules'.

Marius was Consul of Rome an unprecedented seven times and an uncle by marriage of Gaius Julius Caesar.

The Empire

During the 500 years the Legions existed, they were constantly evolving to meet the needs of Rome. The Imperial era began when in 49 BC the then Governor of Gaul, Gaius Julius Caesar, crossed the River Rubicon, the border between what was considered Italy and Cisalpine Gaul, with the XVII Legion. With this military support he established himself as dictator for life - in essence, though not title, the first Roman Emperor.

The Imperial Legion

A Roman Legion consisted of approximately 6,000 men3. Any recruit to the Legion had made a big commitment as he enlisted for the standard term of service of 25 years. The completion of a full 25 years of service was generously rewarded by a land allotment and a good pension. As retiring legionaries were encouraged to settle in frontier areas, this system assisted the colonisation of new provinces and provided a useful reserve force of experienced soldiers in case of trouble.

The only way out of the Roman Army before retirement was by death or severe injury. A man who was discharged as an honourably injured soldier was referred to as a Causarius. The fate of any deserters was execution. Insubordination and cowardice in the face of the enemy could also carry the death penalty - more of that later.

The Basic Equipment of a Legionary Soldier

The basic issue for all men from Legionary to Centurion was very similar:

  • Helmet - a plain helmet with neck and cheek guards. It would have a horsehair crest mounted front to back if the man was an officer (Optio or above). For recognition a Centurion's helmet crest was mounted ear to ear.

  • Helmet liner - this was thick felt and protected the wearer from heavy blows and the heat of the summer sun.

  • Neck scarf - this served to absorb perspiration and could be used as a field dressing if necessary.

  • Tunic - commonly red.

  • Kilt or breeches in cold weather - knee length and commonly red.

  • Caliguli - military sandals. These had metal studs for grip, hard wear and kicking the enemy. The word caliguli may sound familiar as they gave an Emperor his name - when he was young, Gaius Caesar Augustus Germanicus was given a small pair of army caliguli and was considered the army's mascot. He thus became known as Caligula, meaning 'Little Boots'.

  • Gladius - a short sword, this was a thrusting weapon for close combat. This sword gave us the word 'Gladiator'.

  • Scabbard - with shoulder strap hung on the left shoulder, so the sword hung from the right hip.

  • Body armour - Lorica Segmentata plate armour or mail, protecting back, front and shoulders. Lorica Segmentata replaced the earlier chainmail armour around the time of the invasion of Britain in 43 AD. It took some years to reequip all the Legions, so chainmail remained the standard issue armour for the auxiliary units and the marine's units of the Roman navy.

  • Sporran or Apron - a belt with heavy metal-plated leather strips hanging over the groin.

  • Pugio - a military dagger for very close quarter fighting and dispatching wounded enemies.

  • Scutum - a shield. Regular legionaries had a rectangular shield and Auxiliaries had an oval shield.

  • Shield cover - to protect the shield from being soaked in foul weather, preventing it from warping. The cover was removed for battle.

  • Greaves - shin guards issued to Centurions only.

  • Mess kit - standard issue cookware for all ranks.

  • Blanket

  • Kit Bag and Carrying Yoke.

When a Legion was on the march, the men had to carry their personal equipment and possessions with them. The yoke was carried on the shoulder with the kit bag handles hanging from each end of it. If the Legion was attacked on the march, the men simply dropped their kit and rapidly formed battle lines. If they were marching into battle, all their unnecessary kit was left in the care of the transport section.

The Basic Units that Formed a Legion

There was a formal structure within every Legion, with all ranks up to Centurion living, working and fighting together. The purpose of this structure was to create strong bond of trust and comradeship between the men and their junior officers.

A Legion was made up of a series of units. Each unit had a command structure and could if necessary be detached from the Legion and operate independently with their own officers. These units could act as a scouting party, the garrison of a fort, carry out patrol duties, be a supply escort - the list is almost endless. This allowed the commanders huge flexibility in how they used the men under their command.

The only qualification required to join a Legion was that you had to be a freeman: a Roman Patrician (aristocrat), a Plebeian (commoner) or Peregrinus (a commoner from the provinces) or a Liberti, an ex-slave who had been freed having received a grant of manumission. This was at times a little flexible, as there are records of men being granted citizenship on the condition that they joined the Legion. Usually, though, if you were not a Roman citizen you could still join the Legion's auxiliary units such as one of the cavalry support units. The Optio and the Centurion officers of any auxiliary unit would have been Roman citizens.

The medical services were not restricted to Roman citizens, although many were, and Greek physicians were regarded as the best.


A Contubernium was also informally known as an octet. On active service, this was the smallest unit of the Legion and consisted of eight men. This number is not as random as it first appears, as a goatskin Roman tent housed eight men. On active service (or in barracks) these groups of eight men were known as a tent section or contubernium.

They lived, worked and fought together; the term 'a band of brothers' would be a very apt description of these units. This was well thought out; the men of the section were a mixture of different ages and levels of experience, with the older more experienced men steadying the younger men when in combat. This small group was the closest thing the soldiers had to a family. The Contubernium was commanded by a senior man, called the Decanus. Decanus means 'leader of ten'. Although at this time he was in charge of eight men, the title is perhaps a survivor of the time when the Legions were larger. Alternatively the title may have derived from the fact he was in charge of a tenth of a Century. Ten Contubernia made up a Century.


The Centuria or Century was the basic fighting unit of the Legion. Despite a quite reasonable expectation that a Century consisted of 100 men, over time the number varied. This has sometimes caused confusion. The cause of this was reorganisation of the Centuries during the 500 years of their existence.

During the early senatorial period, the years of Rome's early expansion, a Century contained 120 men. This was subsequently reduced to 100, during the late senatorial period. Finally during the reign of Emperor Augustus the Imperial Century was reduced again to 80 men.


When it became necessary for one or two Centuries to be detached to man a fort or for other duties, a small force called a Maniple was created. This simply means 'a handful'. The unit had a temporary standard known as a vexillum, with the legionary appointed to carry the standard being called the vexillarius. This in turn has given rise to a term often used by archaeologists, the Vexillation fortress, meaning a fort manned by a small garrison. It is unclear if the Romans themselves ever used this term.


Made up of six Centuries, a Cohort consisted of about 480 fighting men.

An important thing to remember is the Cohorts were not all of equal strength or experience. This could be due to casualties, retirement and sickness - there was a constant flow of men into any active Legion and they would not be effective until basic training had been completed. Also as the men approached the end of their 25 years' service, they would be in their 40s or older, clearly no longer as agile as the younger men. Over the years a system had to be developed that enabled the commander to use his men appropriately on the battlefield.

The Legion and its Structure

The Legion consisted of ten Cohorts. The men were distributed amongst the Legion's Cohorts by age, battle experience, training and ability.

In a Legion, the Centurions had an order of seniority starting with the Centurion of Century I of Cohort I. In the absence of senior officers he could take charge of the men.

Cohort I

Known as the Primus Pilus or 'first spear', this was the largest of the Cohorts. The First Cohort was the elite core of the Legion and was double-strength, numbering between 800 and 960 men. These, the best troops in any Legion, had the most experience of battle.

This Cohort was double the size of the other Cohorts for a reason. Its job was to be the rock on which an enemy charge would break itself. Once the initial charge of the enemy had stalled, this Cohort normally led the advance, ruthlessly cutting down the enemy as it moved forward. An example of the ruthless efficiency of this system was the battle fought by the Roman Governor of Britain, Gaius Suetonius Paulinus, with his force of 10,000 men. They defeated Boudicca and slaughtered of most of her army of 80,000.

The overall command of the Cohort was given to the senior of the six Centurions that commanded each of the Centuries that formed the Cohort.

The Nine Supporting Cohorts

It should be remembered that Cohort I was not the only Cohort with experienced troops. The men of Cohorts III, V, VIII and X (3, 5, 8 and 10) were also experienced and battle-hardened. The battle casualties of Cohort I were usually replaced by experienced men from these other cohorts.

The second line or reserve was formed by Cohorts II, IV, VI, VII and IX (2, 4, 6, 7 and 9). These contained a higher proportion of inexperienced men and raw recruits. This was very much 'on the job training', and as they gained experience the best men from these Cohorts replaced the casualties of the front line Cohorts to ensure that the front line was kept at full strength. It would be misleading to say the men in these Cohorts were poor quality soldiers - far from it - they simply lacked experience and training. They consistently proved themselves equal to any potential opponents.

  • Cohort II: This is where the new recruits were placed and mixed with more experienced men to steady them in battle and learn by following the example of senior men.

  • Cohort III: Fully trained battle hardened troops.

  • Cohort IV: Another of the weaker training cohorts with a mixture of veterans and new men.

  • Cohort V: Fully trained unit, front line ready.

  • Cohort VI: Made up of inexperienced troops but containing the 'Finest of the Young Men'.

  • Cohort VII: One of the weak Cohorts and a likely place to find trainees and raw recruits.

  • Cohort VIII: Contained men referred to as 'The Selected Troops'.

  • Cohort IX: Another of the Cohorts for the trainees and raw recruits.

  • Cohort X: Made up of men referred to in writings of the time as 'The Good Troops'.

At first the system appears a little odd, but the point of the organisation was to allow any commander to take charge of any Legion and know which Cohorts had the best men. As far as the men of the Legion were concerned, this system developed loyalty to the Legion, to the Cohort and absolute loyalty to the Century.

The Officers of the Legion

Please note that any modern ranks mentioned here are not directly equivalent to the Roman ranks, but only approximate the level of responsibility of the modern military rank. For example, the term 'Non-Commissioned Officer' or NCO is a modern term. Although not strictly correct, it is a useful analogy to describe the system ranks of the Legion well.

The Appointed Officers and Other Ranks

One of the reasons the Legions were such an effective fighting force was the way senior officers were appointed. The concept that developed is still in use today and is called the system of commissioning. This had several advantages:

  1. The most able men could be chosen.
  2. They could be rapidly replaced if found to be inept or there were any hints of disloyalty4.
  3. All commissions were dated or given for the duration of a campaign. Officers could therefore be reassigned without causing any political problems.

These commissioned officers were expected to supply their own military equipment and servants at their own expense.

An army or any large body of men, is a very powerful weapon and it is a good policy to place it in the hands of a loyal and competent commander. As a further safeguard, it is also wise to similarly carefully appoint the commander's junior officers for the exact same reasons. With this in mind, the Emperor and the Senate carefully chose the men they put in command or the Legions. This meant that the selected officers' extended family, wealth and estates were in the hands of Rome and would prove the final forfeit in case of disloyalty.

Officers Appointed by the Emperor or Senate.

  • Legatus Augusti (Imperial Legate) - a general, a senator, a provincial governor, and the overall commander of two or more Legions stationed within in his province.

  • Legatus legionis (Legate) - a senator appointed as commanding general of a Legion, often chosen for his experience after a distinguished career in the Legions starting as a junior Tribune. The Legate could be in command of several Legions - he was often headquarters-based, passing the field command of individual Legions to the senior Tribune under his command. This was not unusual, as Julius Caesar had four Legions under his command when he invaded Britain, each operating individually.

    A Cornicularius (administrator) was also appointed to assist the Legate and the Tribunes.

  • Tribunus laticlavius (Senior Tribune) - the senior of the Legion's six Military Tribunes. An experienced officer, his rank was designated by the broad purple band on his tunic. Acting under direct orders of the Legatus legionis, he was the effective commander of the Legion in the field.

  • Tribunus militum (Tribune) - There were five junior Military Tribunes5 in the Legion, who were the Legion's field commanders. They did not hold equal military status and were ranked in order of authority. All Tribunes were chosen from Rome's Equestrian upper class; they were usually sons of experienced former officers and were prepared for service in the army. They were often inexperienced and reliant on the skill of their Centurions to get the job done. A successful time in the Legions gave these men the opportunity to advance politically when they returned to civilian life. The rank of Tribunes militum was designated by the narrow purple band on his tunic.

  • Quaestor - a senior officer in charge of the Legion's supplies and transport.

Other Officers Appointed within the Legion

The appointment of other officers was made within the Legion - these did not require any political approval or commission, and could be referred to as non-commissioned officers.

The officers promoted from the ranks of the Legion by the Legate or Tribunes, due to their skill and leadership ability, were:

  • Praefectus Castrorum (Camp Prefect) - the third officer in the Legion's chain of command. If the Legatus legionis was not with the Legion, he would serve as the Tribune's second-in-command in the field. A time-served senior Primus Pilus Centurion who had already completed 25 years of service, he was an experienced head the other officers could rely upon. In battle he would command a cohort of auxiliary foot. He was also in charge of the training of the Legion. One of his administrative duties was to ensure that the casualties received the best medical care, making sure the Base Hospital and its staff dealt efficiently with the wounded as they arrived. This included organising post-treatment convalescence of the men at suitable spa towns.

  • The Centurion - the front line commander of a Century. He wore a helmet with a crest mounted from ear to ear and carried a vine cane.

  • The Optio Centuriae - the Deputy Centurion, was recognised by his helmet with a black and white crest mounted fore and aft.

  • The Decanus - the senior Decanus could stand in for the Optio if he fell in battle.

The Standard Bearers

There were many standard bearers in a Legion. Not only did the standards provide a focus for the men on the battlefield, they could be used to give simple visual signals to the men. Each Century had a standard in addition to the Legion's standard. The Legion's standard signified the spirit of the Legion, but all the standards were vitally important as they served as rallying points in the heat of battle; in battle, the men went where their standard went.

All standard bearers ranked above an ordinary legionary soldier. This meant that in extreme circumstances they could take command of small units if other officers were out of action.

  • The Aquilifer - carried the Legion standard. The Aquila (Eagle) is the best known Legion emblem, but it was one of many. Other emblems included the boar, bear, the open hand, and the bull, amongst many others.
  • The Imaginifer - carried the imago. The imago was an image of the Emperor and symbolised the Legion's loyalty to him.
  • The Signifers - carried a signum, the standard for each Century of the Legion, there would be ten Signifers in a Legion.
  • The Vexillarius - carried the vexillum. This standard was a cloth banner, the forerunner of the flag, hanging from a cross shaped staff. It was mainly used in auxiliary units of both infantry and cavalry.

For the purpose of recognition it was customary for standard bearers to wear an animal skin, a practice adopted from the Celtic tribes of Gaul. The animal skins used were boars, bears or lions. The head of the animal was worn on the helmet, and the skin was used as a cloak over the uniform.

The Cornicen or Trumpeters

The Cornicens were important members of the Legion; like a bugler, they were the only method the commander had to rapidly issue movement orders to the Legion while on the battlefield, as verbal orders were masked by the noise of battle. Every Cohort had a Cornicen.

Legionary Designations and Ranks

Any Legion would have a mixture of different types of Legionary soldiers, based upon training, experience and special abilities or skill.

  • Munifex or Miles - The individual private soldier was known as a Miles (plural: Milites) and was assigned to a Contubernium within a Century. These ordinary soldiers formed the bulk of the fighting forces. They had no specialist training and so extra duties were typically confined to labouring or guard duties.

  • Triplicarius - This was not actually a rank but was a reward given to a senior soldier who had special skill. Men with this status received a rate of pay three times that of an ordinary legionary.

  • Vocati - Veteran soldiers.

  • Immunes - Legionary soldiers with additional skills including surveyor, carpenter, builder and mason.

  • Beneficiarius - A title given to a soldier chosen from the legionary troops. They could serve as an orderly or aide assigned to a senior officer, or serve in an administrative capacity within the Legion. The benefits of the status was a pay increase, lighter duties and better chance of promotion.

    • Beneficiarius Consularis - Consular aid.
    • Beneficiarius Tribuni - Aid to a Tribune.
    • Beneficiarius Interpretes - Interpreter.
    • Beneficiarius Notarii - Secretary.
    • Beneficiarius Librarii - Archivist.
    • Beneficiarius Exceptores - Shorthand writer.
    • Beneficiarius Exacti - Recorders or clerk.
    • Beneficiarius Haruspices - Religious seer.
    • Beneficiarius Classis - Fleet quartermaster, often based in the shore forts such as Portchester.

Administration and Supporting Services

The Legion would have a fixed fortified supply base and hospital, normally as an annex within a camp or a legionary fort. When moving through hostile territory, every time the Legion stopped for the night a fortified marching camp would be constructed. The marching camp was taken down each time the Legion moved on, so a potential enemy could not make use of it. This was a very important precaution while campaigning in hostile territory.

The Commissariat Beneficiarii

The beneficiarii clerks and stores orderlies had to keep up with a Legion on the move and needed a well-organised system of distribution. Each Legion had approximately 1,400 mules to be used as pack or draught animals. The problem of feeding the transport animals was one of several reasons operations were restricted to the summer months, as in winter grazing was not available. Large carts and heavy baggage were pulled by oxen.

Support Personnel

  • Explorator - A scout. The term also applied to spies working with forward units.

  • Mensor - A surveyor. A team of surveyors was referred to as Metatore.

  • Cerarius - A book-keeper, named after the cera, the wax tablet he always used.

  • Mulio - A mule driver, part of the impedimenta or baggage train used for carrying the tents, food and tools.

Special Duty Units

It is difficult to determine whether the non-combatants such as field surgeons and clerks were ever included in the roster of a Legion or just worked alongside it.

Medical Staff

This was led by one or more doctor/surgeons Capsarius) and a Medicus or doctor. The doctors and medical orderlies were some of the most skilled of their time. A medical team consisting of a Medicus and several orderlies were a part of every ala or Cohort. The standard of Roman battlefield care was not matched again until the First World War. Many Greeks served as legionary doctors and surgeons as the Greek doctors were widely regarded as the best of the time.

The Medicus was often referred to as Tribunes Medicus as it was a rank or post that was approximately equal to Tribune. The Medicus was appointed by the Senate or Emperor and the title Tribunes was possibly a convenience rank that held no field command but gave sufficient power to overrule the Centurions and get the wounded the best treatment.

It should be noted that every man in the Legion had received training in battlefield first aid, and dressings ware available in the battlefield. This meant the Roman army had one of the highest survival rates for battlefield injures.

Cohors Praetoria

The bodyguards of the senior officers served in this unit. The Tribuni Militum officers were often political appointees who were members of influential families. As some of these men were destined for high political office, extra protection on the field of battle was desirable.

The Artillery

The artillery were a separate unit in combat who were responsible for the transportation, operation and maintenance of the various missile firing machines used by the Legion. The machines loosely referred to as catapults varied widely. They ranged from stone-throwing machines designed to demolish walls and palisades6, to long range bolt-throwers that looked like an oversized crossbow on a stand. These were used against massed enemy troops or defended walls.

  • Onager - A heavy stone thrower. This was used against fortifications and was capable of demolishing fortified gateways and walls.

  • Vitruvius - A ballista or stone thrower, this was used against fortifications, buildings and troop formations.

  • Scorpion - A bolt-shooter used against ships, buildings and troop formations and timber fortifications.

  • Manuballista - A powerful long-range bolt-shooter. Excellent against ships, buildings and troop formations and timber fortifications, it was often mounted on large Roman navy vessels

  • 'Xanten' - A bolt-shooter that was good for siege work and also excellent against shipping and timber forts. What the Romans called these has not been recorded. 'Xanten' is the modern name of the German town on the site of the Roman settlement of Colonia Ulpia Traiana where one was found in recent times.

  • Polybolos - Meaning 'multi-shot', this was a repeating bolt-shooting machine used against fortifications as well as cavalry and troop formations.

The records indicate that in normal circumstances a Legion in the field would be equipped with 10 Onager heavy stone throwers, 30 Scorpion bolt-shooters and 20 Manuballista. Heavy artillery were usually moved by teams of oxen.

The Auxiliary Forces

The Auxiliaries were very important, separate units recruited from the Empire's local, non-Roman population. They were used as an addition to the Legion's forces. Their training was similar to that of the legionary and they were trained in Roman styles of combat. Auxiliary forces were issued different kit to that of the Legions. The main differences were:

  1. They were only ever issued chain mail armour, with bronze or iron helmets.
  2. The shields of all auxiliary units were oval, not the rectangular shield of the Legions.

The issue of different equipment was an important distinction as it enabled their easy recognition and avoided confusion on the battlefield.

It was also procedure that, whenever possible, auxiliary forces were not used in the province in which they were recruited. This was to avoid any possibility of using these men against their own people. That is why there are many records of Gauls serving in Egypt and men from Dacia (Romania) and the Euphrates serving on Hadrian's Wall. However, taking advantage of long standing tribal hostility, some local tribesmen were recorded as being recruited as auxiliary forces and used against neighbouring tribes during the conquest of Britain.

The Roman army had two distinct types of Auxiliary forces: foot and cavalry.

Auxiliary Foot

The Auxiliary Foot were established in units of similar size to a Cohort. The units were led by a legionary Centurion, who was often approaching the end of his 25 years' service, and an Optio. These units were used as transport guards, as garrison troops for forts protecting supply routes or frontier towns. The Auxiliary Foot often included a unit of slingers; a group of men armed with slingshots could be extremely effective on the battlefield. The Auxiliary units were granted a standard bearer and their own standards. Garrisons of forts were often also supported by a unit of Auxiliary Cavalry.

The Auxiliary Cavalry

As the Roman army did not have cavalry in the regular forces, the preferred option was to recruit troops from the native population of the provinces. There were generally two cavalry units. The largest unit was the Ala Milliaria commanded by the senior Praefectus Alae7. This unit had between 720 and 960 mounted officers and troops. These were divided into 32 Turmae of 22 to 30 men, each commanded by a Decurion.

The second unit was the Ala commanded by a second Praefectus Alae. Each Ala had 480 mounted troops, divided into 16 units or turmae of 30 men, each led by a Decurion. The cavalry standard or Draco was carried by the Draconarius.

Officers were Roman citizens appointed as legate commanders of auxiliary cavalry cohorts. Besides supporting the Legion on the battlefield, duties included patrols and scouting, acting as messengers, guarding supply transports and providing bodyguards for senior officers or government officials.

The Auxiliary Cavalry were equipped with a long oval shield, long Celtic style sword and spear, and were protected by a long chain mail coat and helmet. As some helmets even had a nose guard, they were very similar in appearance to a later Norman knight.

The cavalry units were mainly used against lightly-armed foot soldiers or for skirmishing with enemy cavalry. The Romans did not use heavy cavalry as we understand the term today (armoured riders able to use direct force against opponents) - one reason was because, although they had a robust and solid saddle, the stirrup had not yet been introduced8 and so Roman cavalry lacked the extra stability that stirrups would have provided. A Roman horseman could be pulled from his mount comparatively easily. Though this does not mean the Roman military saddle was bad - far from it - the saddle was well designed and had a saddle tree, a frame that distributes the weight of the rider to prevent pressure on the horse's spine. Known as a four horn saddle, it also had two horns at the front that were curved to provide firm support to the rider's legs. The two rear horns were curved slightly outward and prevented the rider from slipping backwards.

Legionary Discipline and Punishment

A life in the Legions was hard. Though the training and discipline were harsh, the men were proud of the reputation of their Legion. Though most would willingly fight against almost overwhelming odds and win, things could go wrong.

There were many minor offences that could be committed in the Legion, all punished in relatively minor ways. Punishment included fines deducted from the offenders' pay, extra duties on patrol or guard, or demotion. Digging latrines was universally unpopular. For major offences such as desertion, murder, insubordination on the battlefield, and cowardice in the face of the enemy, they could face the death penalty..

Officers of the Legion were not above punishment; minor offences could lead to the disgrace of being reposted to a minor command or even dismissal. Most of the officers above the rank of Centurion were serving in the army to gain a good military reputation for senatorial service in later life. If things went wrong while they were in command they faced a ruined reputation, humiliation in Rome and no political power or public life. For serious offences, the offender could face the death penalty. If he did not fall on a sword or take poison he could choose death by beheading. This was considered a more honourable fate than crucifixion.


For larger groups such as a Century, Cohort or even an entire Legion, the sentence of decimation could be ordered by the commanding general. Decimation means 'one of ten', and was a psychological as well as a physical punishment. A condemned unit had to draw lots to see who lived. One man (who picked the black token from a jar) out of every ten was chosen to be beaten to death by the lucky men who picked the nine white tokens. The psychological twist was the men were killed by their close comrades who had to live with the memory. That meant if a Century underwent decimation, 72 men issued with pickaxe staves had to beat to death the eight men who were chosen by fate for execution. The unit had to live with the disgrace of the punishment for many years. Any awards the unit had won were also declared void and removed from the standard.

Stoning and Crucifixion

The main punishments for individuals and small groups at the time were stoning or crucifixion. With stoning the victims were encircled by a group and heavy stones were thrown at them until they died.

With crucifixion, victims were tied or nailed to wooden crosses. The nails were not put through the hands but just above the wrist where the bones would support the victim's body weight, ensuring they took days to die. The victims were placed in prominent places, such as by gates, to serve as a deterrent.

When Emperor Constantine and his mother, Helena, became Christian in about AD 310, it meant that Christianity became the religion of the Empire. This meant the army abolished the mandatory death penalty for Christians found in its ranks.

Before we judge the Romans too harshly, give this some thought; if stoning, crucifixion and decimation were replaced with flogging, hanging and firing squads, you have a similar level of punishment brutality that was in use in the British army from the time of Cromwell to the First World War.

The Builders of the Empire: A Lasting Legacy

A Legion was also tasked with consolidating newly conquered provinces. As engineers were a part of a Legion, they were given the task of building roads, bridges and fortifications. Hadrian's Wall and the numerous stone forts around Europe give witness to this.

After the fighting was over, the Legions' engineers also built towns and public buildings such as markets, bathhouses, mills, harbours, temples, hospitals. In short they were a force not just of conquest but of colonisation, leaving in their wake men who had completed their 25 years with the Eagles who settled new areas and helped populate and 'Romanise' the new settlements.

The Roman Military Road Network

As the Legions expanded the Empire, it was crucial that communications were maintained as they advanced; supply lines needed to be established and new roads built9. As the Legions advanced, new settlements sprang up along these roads, spreading Roman culture. A web of minor roads spread from the major routes to the smaller settlements, and trade of all types flourished, which funded the Empire's administration and further expansion.

Using the new roads a message could be carried at a rate of approximately 30 miles (47 kilometres) per day. Imperial dispatches were another matter. Imperial messages were carried by a relay system similar to the US Pony Express and could achieve 500 miles (800 kilometres) in 24 hours, or about 20 mph.

Examples of Roman roads have been discovered throughout Europe and Northern Africa, totalling over 50,000 miles or 80,000 kilometres, many of which have been resurfaced over the years and are still in use. There are examples in all the countries that the Romans occupied10. For example, the best known parts of the Roman road system in Britain are:

Roman Colonisation

The Roman colonisation process could be briefly summed up as:

  • Traders who scouted the lands.
  • Legions who conquered the lands.
  • Merchants who exploited the lands.

Traders do business with the native inhabitants and, as they travel, they explore new territories. Eventually information collected by the traders would reach the Legions, the Senate or even the Emperor. This influenced the decision about whether to dispatch the Legions to annex the new lands. Afterwards, merchants moved in following the Legions and set up formal trade routes, maximising the flow of trade revenue from the new province. The tax collectors followed in the wake of the merchants, funding the Legions and allowing the Empire to continue.

Or as Julius Caesar said in his dispatch to the Roman Senate:

Veni vidi vici (I came, I saw, I conquered).
1The Urban Tribes of Rome were Collina, Esquilina, Palatina, and Suburana. The Rural Tribes were: Aemilia, Aniensis, Arniensis, Camilia, Claudia, Clustumina, Cornelia, Fabia, Falerina, Galeria, Horatia, Lemonia, Maecia, Menenia, Oufentina, Papiria, Poblilia, Pollia, Pomptina, Quirina, Romilia, Sabatia, Scaptia, Sergia, Stellatina, Teretina, Tromentina, Velina, Voltinia and Voturia.2One of the longest serving Legions, the XIII Gemina Alba Iulia (Julia) was one that was created at this time. Already one of the longest serving Legions when it was levied by Julius Caesar in 57 BC, it continued until after 400 AD, having given about 500 years of service.3Serving soldiers were forbidden to marry, so the only females in their life were hired comforts not allowed in the picket lines.4There were always well paid spies in the Legion reporting back to Rome.5Not to be confused with the rank of Senatorial Tribune, who was a public official.6A defensive row of wooden stakes, often accompanied by earth banks.7The title or rank of Praefectus or Prefect was widely used and could refer to a military officer, town governor or civil administrator.8Though used in Indian and Chinese civilisations from around the 2nd Century BC, the stirrup failed to reach the West for over 500 years.9To give an idea of the Empire's extensive communication system, the following maps show some of the major ports and naval bases in Europe and North Africa. These were connected by major roads. This shows the huge system created by the Legions. Follow the links to see Roman Fleet Ports and Military Establishments in Britain and Northern France. or Britain, Europe and North Africa.10Roman roads can be found in the following countries: Austria, Albania, Belgium, Britain, Bulgaria, France, Germany, Greece, Macedonia, Netherlands, North Africa, Romania, Serbia, Turkey, Spain and Portugal.

Bookmark on your Personal Space

Conversations About This Entry

There are no Conversations for this Entry

Edited Entry


Infinite Improbability Drive

Infinite Improbability Drive

Read a random Edited Entry

Categorised In:

Written by


h2g2 Entries

External Links

Not Panicking Ltd is not responsible for the content of external internet sites

Write an Entry

"The Hitchhiker's Guide to the Galaxy is a wholly remarkable book. It has been compiled and recompiled many times and under many different editorships. It contains contributions from countless numbers of travellers and researchers."

Write an entry
Read more