The Army of Augustus - the 'classic' legion

The army as operated from the time of Augustus can generally be referred to as the 'classic' legion, the armed body of men which most imagine in their minds upon hearing the word 'legion'. And it is this state of the legion which is largely recreated in illustrations or Hollywood movies.

Under Julius Caesar, the army had become a highly efficient and thoroughly professional body, brilliantly led and staffed.
To Augustus fell the difficult task of retaining much that Caesar had created, but on a permanent peace-time footing. He did so by creating a standing army, made up of 28 legions, each one consisting of roughly 6000 men. Additional to these forces there was a similar number of auxiliary troops. Augustus also reformed the length of time a soldier served, increasing it from six to twenty years (16 years full service, 4 years on lighter duties).

The standard of a legion, the so-called aquila (eagle) was the very symbol of the unit's honour. The aquilifer who was the man who carried the standard was in rank almost as high as a centurion. It was this elevated and honourable position which also made him the soldiers' treasurer in charge of the pay chest.
A legion on the march relied completely on its own resources for weeks. To make camp each night every man carried tools for digging as well as two stakes for a palisade.
Apart from this and his weapons and armour, the legionary would also carry a cooking pot, some rations, clothes and any personal possessions.
Weighed down by such burdens it is little wonder that the soldiers were nicknamed 'Marius' Mules'.

There has over time been much debate regarding how much weight a legionary actually had to carry. Now, 30 kg (ca. 66 lbs) is generally considered the upper limit for an infantryman in modern day armies. Calculations have been made which, including the entire equipment and the 16 day's worth of rations, brings the weight to over 41 kg (ca. 93 lbs). And this estimate is made using the lightest possible weights for each item, it suggest the actual weight would have been even higher. This suggests that the sixteen days rations were not carried by the legionaries. the rations referred to in the old records might well have been a sixteen days ration of hard tack (buccellatum), usually used to supplement the daily corn ration (frumentum). By using it as an iron ration, it might have sustained a soldier for about three days. The weight of the buccellatum is estimated to have been about 3 kg, which, given that the corn rations would add more than 11 kg, means that without the corn, the soldier would have carried around 30 kg (66 lbs), pretty much the same weight as today's soldiers.

The necessity for a legion to undertake quite specialised tasks such as bridge building or engineering siege machines, required there to be specialists among their numbers. These men were known as the immunes, 'excused from regular duties'. Among them would be medical staff, surveyors, carpenters, veterinaries, hunters, armourers - even soothsayers and priests.
When the legion was on the march, the chief duty of the suveyors would be to go ahead of the army, perhaps with a cavalry detachment, and to seek out the best place for the night's camp.
In the forts along the empire's frontiers other non-combatant men could be found. For an entire bureaucracy was necessary to keep the army running. So scribes and supervisors, in charge of army pay, supplies and customs. Also there would be military police present.

As a unit, a legion was made up of ten cohorts, each of which was further divided into six centuries of eighty men, commanded by a centurion.
The commander of the legion, the legatus, usually held his command four three or four years, usually as a preparation for a later term as provincial governor.
The legatus, also referred to as general in much of modern literature, was surrounded by a staff of six officers. These were the military tribunes, who - if deemed capable by the legatus - might indeed command an entire section of a legion in battle.
The tribunes, too, were political positions rather than purely military, the tribunus laticlavius being destined for the senate.
Another man, who could be deemed part of the general's staff, was the centurio primus pilus. This was the most senior of all the centurions, commanding the first century of the first cohort, and therefore the man of the legion, when it was in the field, with the vastest experience. And it was also he who oversaw the everyday running of the forces.

Together with non-combatants attached to the army, a legion would count around 6000 men.
The 120 horsemen attached to each legion were used as scouts and dispatch riders. They were ranked with staff and other non-combatants and allocated to specific centuries, rather than belonging to a squadron of their own.

The senior professional soldiers in the legion was likely to be the camp prefect, praefectus castrorum. He was usually a man of some thirty years service, and was responsible for organization, training, and equipment.

Centurions, when it came to marching, had one considerable privelege over their men. Whereas the soldiers moved on foot, they rode on horseback. Another significant power they possessed was that of beating their soldiers. For this they would carry a staff, perhaps two or three foot long. Apart from his distinctive armour, this staff was one of the means by which one could recognise a centurion.
One of the remarkable features of centurions is the way in which they were posted from legion to legion and province to province. It appears they were not only highly sought after men, but the army was willing to transport them over considerable distances to reach a new assignment.
The most remarkable aspect of the centurionate though must be that they were not normally discharged but died in service. Thus, to a centurion the army was truly his life.
Each centurion had an optio, so called because originally he was nominated by the centurion. The optiones ranked with the standard bearers as principales receiving double the pay of an ordinary soldier. The title optio ad spem ordinis was given to an optio who had been accepted for promotion to the centurionate, but who was waiting for a vacancy.
Another officer in the century was the tesserarius, who was mainly responsible for small sentry pickets and fatigue parties, and so had to receive and pass on the watchward of the day. Finally there was the custos armorum who was in charge of the weapons and equipment.

Battle Order

Front Line

Second Line

The first cohort of any legion were its elite troops. So too the sixth cohort consisted of "the finest of the young men", the eighth contained "selected troops", the tenth cohort "good troops".
The weakest cohorts were the 2nd, 4th, 7th and the 9th cohorts. It was in the 7th and 9th cohorts one would expect to find recruits in training.