Organization
A LEGION comprised 6000 soldiers. It was made up of 10 COHORTS, each containing 600 soldiers. The cohort was composed of 3 MANIPLES (200 soldiers each). A maniple contained 2 CENTURIES (one hundred men = a century) and their commander was a CENTURION.
In Gaul, auxiliary forces marched with the legions. They were light-armed soldiers supplied by Rome’s allies or subject territories. In battle they were usually stationed on the wings, but if the commander wasn’t sure of their courage or loyalty he placed them between the Roman formations so they couldn’t flee. In some battles there were as many auxiliary soldiers as Roman legionaries: javelin-throwers, archers, and slingers.
About 300 CAVALRY usually accompanied the legions. The cavalry was divided into SQUADRONS, TROOPS, and DECURIONS. In Gaul they were usually non-Romans and Caesar didn’t trust them very far. He used them to scout, to skirmish, and to chase enemies on the run but he never depended much on them. (Note: The Roman army changed over the years. These data refer to Julius Caesar’s army in Gaul in 58–51 BC. His legions often fell far short of these numbers).
Battle Deployment
Battle deployment for the legions was in three lines, one behind the other. Four cohorts in the front line, three in the second, and three more in the third. This faced the enemy with a solid front while allowing for rapid manoeuvering for assistance.
Standards
A military parade, showing soldiers carrying military standards, as depicted on Trajan’s Column, Rome
Standards were long poles decorated with symbols. The symbol for a legion was the EAGLE, but the cohorts had their own standards with images of gods, goddesses, animals, banners, and other objects such as phaleras (metal disks: see AWARDS below). Soldiers grouped behind their standards, which were used to signal the start of a march or manoeuvre.
Armor and Weapons
All the soldiers in the legion carried a backpack and wore the same outfit: body-armor made of leather and metal. They wore sandals like these:
They each carried a wooden shield covered with leather and metal, a sword, and a javelin.
The March
The army marched in columns. Each legion had its own baggage, carried in wagons or by pack-animals. They set out just after dawn and marched until noon (the seventh hour), covering roughly fifteen miles a day, unless they were in a hurry. Caesar’s troops often made forced marches of eighteen miles and more. See this video of the Battle of Philippi, fought between the armies of Mark Anthony and Brutus.
Fortified Camp
As soon as they ended their march they set about building a camp for the night. The camp was laid out like a city, with broad avenues and side-streets and square city-blocks. There was even a main square or forum. It was surrounded by high walls with a fence; and all around it was a deep ditch. The camp-model was the same everywhere: it didn’t depend on the terrain. That way every soldier knew from habit what he should do when the army stopped for the night, and he felt safe and at home where he slept.
Model of a Roman army camp by Hans Weingartz (Wikimedia GNU photo)
It wasn’t only for foot-soldiers. The cavalry was there too, with all its horses. All the food and baggage and wagons that an army needs, plus any booty it may have won—and booty included livestock—all had to be brought in and protected. Such a camp could easily become a big mess, with men and animals getting into each other’s way. But organization was the Roman forte and they were able to keep good order.
Roman Time
The day (sunrise to sunset) was divided into twelve HOURS. The length of the hour changed with the seasons. The eleventh hour in winter, for example, would have been around 4 p.m. our time. Roman noon was always at the end of the sixth hour. Night (sunset to sunrise) was divided into four WATCHES of equal length. The third watch began at midnight.
Discipline
It was fearsomely strict. A soldier on guard duty during a campaign who was found sleeping was clubbed to death by his comrades. Execution was the punishment for several other offences, too, such as giving false evidence, stealing, homosexual practice, and committing the same fault three times. Leaving your post and throwing away your weapon on the battlefield was also punished with death. If an entire group of soldiers turned tail in a battle, their sentence was DECIMATION. The tribune called an assembly of the legion and ordered the offenders to the front. In a dramatic speech he described their crime and called them cowards. Then he asked each of them to choose a number. By lot, one out of every ten men was chosen to pay the penalty. At the tribune’s order, they were beaten to death. The rest of the guilty men were allowed to live, but they had to sleep outside the camp walls, unprotected; and they were given barley—horse food—to eat rather than wheat. They lived the rest of their lives in disgrace.
Awards
Caesar personally praised before the entire army any man who had acted in battle with outstanding bravery. He was awarded a spear if he had voluntarily exposed himself to danger and wounded an enemy; and a cup if he had killed and stripped one. A valient cavalryman was presented with horse-trappings. The first man to scale the wall of an enemy city and the soldier who had saved a comrade’s life were given a golden crown—the highest distinction. Other awards included phaleras (gold, silver, or bronze disks worn by soldiers on parade), torques, and armbands. Army units also received phaleras for distinguished action and these were mounted on their standards.
Length of Service and Retirement
A legionary served for twenty years or sixteen campaigns before he was discharged, but he often re-enlisted. The pay was bad so he counted on booty. War booty included money from the sale of captured enemy, who were made slaves. Slave-dealers followed the armies and paid cash for the defeated soldiers and their families. Caesar, for example, sold 53,000 Aduatuci and divided the money among his soldiers. At retirement a veteran was often given a pension and even a grant of land somewhere to settle.
My chief sources for these facts were Polybius’ The Rise of the Roman Empire, translated by Ian Scott-Kilvert, Penguin Classics, 1979, and Caesar’s The Gallic War, translated and with excellent notes by Carolyn Hammond, Oxford World Classics. 1996 ..
Great Names in History 
thank u so much not
It depends on the year
Has anyone found a roster of Roman Officers in Caesar’s ary, especially those given land in England? I’m looking for the source of the surname “BONELL.”
John Bonell: No, John, I can’t. Nor do I know who to send you to. Sorry.
Can you verify a statement made by my grandfather that an officer named BONELL in Caesar’s army given land in England?
Steve: Thanks. I should say that this post is not for scholars and professionals. The figures I give (taken from the translator’s notes in my Caesar’s Gallic Wars) are meant to give the general reader a rough idea of just how many soldiers Caesar is talking about when he says a “legion” or a “cohort”. I know it is impossible to have the exact numbers, for the reasons you give. For my paragraphs on discipline and camps, I relied on the report of a Greek (Polybius) who, though he actually moved around with a Roman army, lived almost a hundred years before Caesar. But his first-hand description of Scipio’s army is the best and most lively that I know.
A century in an ongoing military campaign was prone to men being sick, wounded, killed in battle, taken prisoner by the enemy, deserters and soldiers on furlough. So to estimate true numbers of individual Legion, maniple and cohort strength was always a problem without backing written military records and census on troop strength and levels. Much of the histories written documentation is lost to posterity. And historians who wrote sometimes 100 to 150 years afterwards are prawn to the exaggeration almost mythological expansion of these times. Also the winners usually get to write the history. Gaul, Belgica and the German tribes had few written records of note at the time. So these histories are often one sided and inflated into a distortion of what actually happened. Back in Rome and Romanized Provinces much more is known. Yet so much was lost in The fall of The Western Roman Empire and The Sack of Rome itself that many of these issues remain unclear and thus open to debate. Many of the points made in the main article are true. But full clarity we will never have. At most we make very good assumptions using the data left to us and Archealogical and Linguistic analysis to form the best guess of how a legion functioned. On a long campaign there had to be some attrition and Ceaser filled gaps with soldiers from concquered Celts and Germans to augment his forces. Most of my information comes from The History Of Rome Volumes 1-5 as well as many searches on the web when reading.
Anonymous: I gave my sources. Yours?
This is rubish♣
very helpful! thnx so much!
There were always 100 men in a century. that’s the whole point. the word century derives from the latin word “cent” meaning one hundred. (the word still means 100 in french, which takes much of its modern language from latin after caesar’s conquest.)
To get an 80-man century, you have to neglect the noncombatant bearers with each century.
Elizabeth: I gave my source. Yours?
if you make a website then it should be right
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a roman century was actually 80 men not 100
commanded by as you say a centurion in some cases a primus pilum(first spear centurion)commanded a maniple and if no other centurion was available then centurys were handed over to an optio(sargeant) until one was available
the roman backpack was late in design formerly the carried stuff on a pronged stick or pole as far as punishments another one that was popular was to be caned by the centurion also a simple way to tell a roman citizen soldier from a foreign conscript was by the shape of the scutum(shield)one bieng rectangular and the other sort of ovoid