About Ranks in a Roman Army

Although the Roman Army, and especially the Imperial Roman Army, serves as the basis of military organization for the entire world, it's ranking system was one of the things that was not transmitted. This makes its workings a little peculiar to those unfamiliar with it. Everyone knows what a Centurion was, but few understand the role of a Tribune, or how one went about becoming one. However, the system met Roman needs well enough, and knowledge of it is crucial to an understanding of the Roman military.

Time Frame

The Roman Army was an institution that spanned several centuries of time, and over this period the army itself underwent substantial evolution. This information refers directly to the Roman Army as it was known during the classical period of the Empire, from the reign of Augustus Caesar to that of Commodus--27 B.C.to 192 A.D.

Function

Before considering the ranks of the Roman Army, it is necessary to consider the Army's organization. The basic unit of the Roman Imperial Army was the Century, typically consisting of 80 men and 20 servants or specialists. Next up was the Cohort, made of six Centuries, except for the 1st Cohort, which was double-sized. Ten Cohorts made up a Legion. The Army also had a number of allied units, typically Cohort-sized, that were often called Auxilia.

Types

At the bottom were the Legionarii, the rank and file of the Army. These men were either conscripts and volunteers in the Republic, or professional volunteers under the Empire. Among, but somewhere removed from the ranks of the Legionarii were the Immunes, the specialists such as craftsmen, clerks, and doctors.

Next up the rung were those who would correspond to junior non-commissioned officers, such as corporals and junior sergeants. The primary rank in this category was the Optio, or the Centurion's deputy. There were also the Aquilifers and Signifers, who bore the standards of the Legion and the individual Centuries respectively, and the Cornicen, or bugler.

The core of the professionals among the Roman Army were the Centurions. Ostensibly a Centurion led a Century, but there was a seniority system among them. Within a given Cohort, the Centuries were ranked, with the Centurion of the senior Century being the leader of the Cohort, or Pilus Prior. Among the Cohorts was a similar structure, with the leader of the senior-most 1st Cohort being the Primus Pilus. This was the highest rank in the professional Imperial Army, and they were typically regarded as the most wizened and expert soldiers in the Army. Finally, there was also the Camp Prefect, a very senior Centurion of long service who served as an adviser to the Legate and third in command of the Legion (typically after the most trusted Tribune, who served as second in command).

Commanding the Legion was the Legate. He was assisted by officers who were senior in rank, but not necessarily in age or experience. These were the politically appointed Tribunes, and in Republican times some Tribunes were even elected by the Roman people. Tribunes had no role set by their rank, and could either act as staff aides, senior commanders within the Legion or general purpose troubleshooters. Sometimes attached to a Legion was a Queastor, an elected official on the bottom rung of the Cursus Honorum, or "honors ladder" of Roman political office. These would function as Quartermasters. What all these officers had in common was that they all entered the Army by direct appointment of the Emperor, and were not necessarily full-time, professional soldiers.

Above the Legate was typically the commander of a collection of Legions and Auxilia units that would make up a field army. This commander would also typically combine the governorship of one or more provinces into his command, and therefore hold the appointment of Proconsul or Propraetor.

Features

Separated from the Legions were the ranks of the Auxilia. These were commanded by officers called Prefects, who were seconded by officers who were called Decurions or Centurions. The organization of a given allied unit could vary widely, given that these were raised principally from non-Roman legions and could vary in composition from archers to spearmen to heavy cavalry. However, the Romans did try to impose a modicum of standardization on the Auxilia.

Considerations

Even under the Empire, political favor was always a consideration in promotion through the ranks, and especially so as one progressed. While it was conceivable to rise from ranker Legionarii to a mid-ranking Centurion on sheer merit, to go further would require political sponsorship and the favor of the Emperor. Furthermore, the command ranks of the Legion were on a completely different track from the professional ranks of the rankers and Centurions. Tribunes, Legates and Generals were drawn from the rank of the upper-class Equestrians and noble Senators.

It is plausible that a common citizen could enlist as a ranker, and then rise to become a Legion's Camp Prefect through hard work, making good connections with his superiors and with luck. Such men were often given substantial bounties by the Emperor upon retirement, allowing them to enter the ranks of the Equestrian Order. However, that would open a career as a Tribune, Auxilia Prefect or Legate to their sons, not to them personally.