The Roman Army After Marius' Reforms

An Introduction

Page 3

Marius' Reforms

The Reforms

The Legionnaires and Their Equipment

After abolishing the property qualifications, Marius did away with all the distinctions based on social class. Marius removed the velites and the cavalry from the Roman army completely (their roles going to the allied troops and native soldiers). All legionaries were identically armed with a pilum and gladius and the age based lines were abolished.

The Roman army had always been infantry heavy, and now under Marius it was doubly so. He decreed that all the soldiers would carry their tents, weapons and food themselves - earning the Legions the nickname "Marius' Mules." The humour aside this was an excellent change, as it created the responsive, capable soldiers people today associate with the Roman Legions.

An addition, often overlooked, change that Marius instigated was the redesign of the pilum. Marius had it altered to so that the sharp head was attached to the shaft by a thinner joint (creating the typical image we have for the pilum today). This ensured that when the legionaries threw the pilum, the head would break off on impact and their enemies would be unable to pick it up and throw it back.

The Structure of the Roman Army

Another of the critical changes was the reorganisation of the Army as a whole. Marius did away with the maniple as the basic unit (although administratively they remained for a short time) and made the cohort the main tactical sub-unit. Each legion now comprised ten cohorts.

Cohorts were made up of about 480 legionaries, divided into six centuries of about 80 men (only in the very earliest days of the Roman Legions was a century actually 100 men...), led by a Centurion. In future years, the prima cohors ("First Cohort") would be increased to double strength (approximately 800 men) and be the "elite" of the legion.

The alae were no longer the "allies" covering the Roman wings, but cavalry specialists recruited from the auxiliaries. Organised into units of either 512 or 768 men these provided a strong, fast screen to defend the legions.

To encourage loyalty to the legion and provide a rallying point, Marius also introduced the silver aquila ("eagle") as the main standard. This symbolised the pride and identity of the legion and developed myths of its own.

The final, significant, change introduced by Marius was the concept of promoting soldiers from within the ranks. Again, born out of expedience (the advantage of having skilled, capable soldiers leading the centuries as opposed to political appointees was significant for the Roman army) this change had additional consequences. The newly promoted soldiers were likely to be even more loyal to their General and resistant to commands from the quaestors and other (appointed) officers. Likewise, the soldiers themselves were likely to show more loyalty to "one of their own."


Following on from his experiences in the Roman Army, Marius introduced some wide ranging reforms which drastically altered the Legions. While there is no reason to believe any political or social motive for the changes - most of the evidence points to Marius making these changes simply to increase the combat effectiveness of the legions - there is no doubting the long term effect his reforms had.

Marius created, for the first time, a professional army made up from landless citizens. These soldiers were capable, and willing, to fight all year round and had little ties to "home." A significant result of this meant that the soldier, owing no allegiance to Rome, was often more loyal to his General than the country he defended.

From a purely military point of view, the reforms helped change the already efficient Roman army into what could best be described as a killing machine which had no equal for nearly 500 years. After the set backs of Arausio this was welcomed by the Roman people and Marius was repeatedly elected consul. Even in his late sixties Marius was able to lead the Roman army during the Social Wars of 91 - 88 B.C.

It would probably not have been possible for Marius to predict the far-reaching consequences of his reforms, but his "New Model Army" would provide the basis for Julius Caesar crossing the Rubicon in 49 B.C. and for the later Praetorian Guards. Unfortunately for the Romans, one of the longest term shifts this military change caused was the power the Praetorians could wield when it came to finding new emperors. Even from the time of Marius it became quickly apparent that the way to power in Rome now lay in controlling the legions.

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Sources Used

Haywood, J., "The Romans," Andromeda, Oxford, 1994

Marks, A., & Tingay, G., "Romans," Usborne, London, 2003

Cite this work

Wake, T., "The Roman Army After Marius' Reforms," http://
, 28 February 2006.

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