The Roman Legion and it's Military Structure

The roman legion was really effective and modern for its time. With the help of the structured army the Roman empire is one of the most known empires in the world. In this article I am going to explain to you what the military structure of a single legion was.

Lets start at the beginning, the smallest known group within a legion was the Contubernium, this was a group of eight man who shared a tent, had guard duty and had each others back in battle. It was like a squad, and with a squad comes a squad leader in this case the Decanus he was chosen within the Contubernium.

Multiply the Contubernium by 10 and you got yourself a Century. A group of eighty men and at the head of this Century a Centurion. The Centurion was the first in command. The second in command was the Optio, he was mostly in charge of training and disciplining the men in the Century.

6 Centuries together were a Cohort a total of 480 men. Strangely enough there was not a function as Cohort leader, the leader of the cohort was the most experienced centurion within the Cohort.

Now here is where it becomes a bit strange everything what I told you about the Cohorts above is true except for the first Cohort. The first Cohort consisted of a Century of 160 men and there were a total of 5 centuries in the first Cohort which made the first Cohort 800 men strong.

Just like the other Cohorts, Centurions were chosen among each other. The most experienced Centurion of the first Cohort was chosen to become the fourth in command, this person was called the Primus Pilus. As you can imagine being a centurion in the first Cohort was higher and more prestigious then being a centurion in the other Cohorts.

The thirth in command was the Camp Prefect he was like a quatermaster who was in command of fortifications and supplies, Yet the Camp Prefect had to be a Primus Pilus himself and was therefore way more experienced. You could see him as a veteran of the legion.

The second in command was the Military Tribune whenever you wanted to go in political office and you had to get some experience that position was mostly filled by those people. Now we have two structures, the new one and the old one. The old one consisted of 6 military tribunes who formed together the military tribune and they each took turns in commanding the Legion.

The new structure consisted of 1 military tribune who had all the responsibility and 5 secretaries who had no responsibilty whatsoever. The last one is in my opinion also the best one. And finally the commander of the legion called a Legate this person was appointed by the senate to lead a certain legion for an amount of time.

There is a video summary about roman army structure which you can watch down below: