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 short of these numbers).
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 assistence.
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 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.
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.
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.
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.
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.
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