I have a lot of respect for today’s service members. A lot of the time they spend training for one job, only to be given a completely different assignment, and are forced to adapt. They are a highly professional, well-trained, and well-equipped fighting force. The modern professional military we take for granted did not spring up from the ground though. As the Doctor once put it, the Roman military is “The greatest military machine in the history of the universe”. The Doctor wasn’t far off either; the Roman military single handedly changed the nature of warfare and gave rise to the concept of a professional army.
To understand how drastically the Romans changed things requires some understanding of how militaries existed previously. In the Western World, the Greeks and Persians commanded the best militaries of their day. The Persian military was made up of conscripts from its conquered territories, experienced and well regulated troops that enabled their large empire to survive. What they did better than anyone was logistics though. The Persians could gather large armies and march them quickly, thanks to an impressive road system and satrapy system of governance. Herodotus gives some idea of how impressive this Persian fighting force actually was; he tells of the army drinking entire rivers dry.
But as 300 and Herodotus taught us, the Greeks beat the Persians, and under Alexander the Great, conquered and ended the Persian Empire. While there was some uniformity throughout the Greek world, each city-state had a military unique for their individual societies. The Spartan military was one of the best among the Greeks, but unique to their society. Spartan men were trained as hoplites since age 7, and this was their only real profession in life. This only worked because they had a large population of slaves (helots) to do the rest of the work, however, which left the citizenry to dedicate themselves to military matters.
Other Greek city-states, like Athens, had somewhat different militaries. In Athens, the army was assembled on a yearly basis. Only citizens in the “hoplite” property class served as hoplites, however. This is because hoplites, knights (hippeis) and even the lower classes—who served as slingers, javeliniers, or other “light infantry”—all provided their own equipment. Hoplites, the heavy infantry, wore a lot of equipment (which is what the word “hoplite” means), and this was not cheap. Only those wealthy enough to afford their own horses—the knights property class—could serve as cavalrymen. Athenians would train with their parents or siblings, inheriting or buying their own equipment; there were no military academies or standing bases for year-round training and uniformity. Usually an army disbanded during winter as well; there were few times when it was necessary for an army to stay mobilized during winter, and it was cheaper and easier to re-mobilize in the spring. They also tended to coordinate campaigns around harvest seasons, in order to disrupt an enemy’s grain supply.
Despite the lack of organized training, demobilization, and the need for citizens to provide their own equipment, the Greeks were almost incessantly at war, and this aided the Greeks in expanding and eventually defeating the Persians. War was the natural state of diplomacy in the Greek world, which meant they were receiving yearly experience and drilling. This offset the lack of standing armies and training camps. The Persians were not as militaristic, at least not on the same scale, which meant fairly green Persians were facing off against veteran Greeks during the Persian Wars. Similarly, they faced veteran troops under Alexander the Great.
The other great asset for the Greeks was the heavy hoplite and the phalanx formation. The main force of Persian armies were light infantry; lightly armored troops with wicker shields, swords, and spears. In the deserts of the Middle East this type of army proved very effective. The light armor allowed quicker movement, independent combat, and prevented the troops from overheating. The Greeks fought as hoplites, with heavy chest plates, helmets, greaves, and of course, the large round shield (hoplon). They fought in the tightly coordinated phalanx, creating a wall of spears and shields. Up against the Persians, the hoplite phalanx was able to break the Persian lines, like battle tanks of the modern age.
In the early days of Rome, they fought much like the Greeks. They had a hoplite system and conscription. After a few setbacks with neighbors, the downside of phalanx army became apparent. Like a tank, the phalanx was powerful and deadly, especially from the front. But it was terribly slow, fairly immobile, and weak from the flanks. So, more like the WWI early tanks. In the hills of the Italian countryside, the Romans found themselves struggling more than they cared to. As a result, they switched to the “maniple” system.
If you’ve played Rome: Total War, you have an idea of how the maniple worked. The army was divided into centuries of 80 men, maniples of 160, cohorts of about 480. Troops were separated by similar property classes; hastati, principes, and triarii, with velites as light infantry and javeliniers. Although Greeks and Romans had units, battles were pretty much just two giant mobs of infantry going at each other. The maniples allowed individual units to function rather than massed infantry. When you look at armies since and modern armies today, you see this type of division and unit control. Individual centuries and cohorts could operate cohesively, and therefore provided the flexibility the Romans needed.—similar to the division level, the company level, and the platoon level in modern militaries. The Romans operated in maniples through their conquest of Italy, the Punic Wars, and much of the history of the Roman Republic. The next evolution of the Roman army was the infamous Roman Legion.
Gaius Marius was a Roman general in the late 2nd century BC, and helped create the first professional army. Like the Greeks, Roman war was not a poor man’s endeavor. Romans paid and provided for their own equipment. The most significant change Marius instituted was to standardize equipment and service with the general and state providing for the legionaries. Every legionary had the same equipment, paid partially by their general. This change was monumentally important for modernizing the military. The property classifications that served as the basis of the armies of the Greeks and Romans became obsolete; everyone was a standard legionary regardless of personal income, everyone received the same equipment.
Another change was in structure. Centuries and cohorts were kept, but the maniple was mostly discontinued as a separate unit. The cohort became the main unit of a Roman army, with 10 cohorts comprising a single legion. This made it easy to mobilize, move, and fight, and as pretty much the system until Late Empire changes and the fall of Rome. Caesar’s Gallic Wars demonstrate the effectiveness of cohorts, with commanders leading single or several cohorts detached from the main force. The Roman legion was so effective, the Empire only started to struggle militarily when its enemies began copying it.
The other fundamental change Marius initiated was in strategy. Pop quiz: what is the single most important piece of equipment for a Roman legionary? For Marius, it was this.
Starting with Marius, Roman armies became experts at earthen works and engineering. Wherever they went, the first task for Marius’ troops was to dig in, or build a fort. In addition, to keep baggage trains at a minimum and legions capable of operating independently for several weeks, Marius’ troops were required to carry packs of their own equipment. Because of the constant digging combined with the equipment each legionary handled, the legionaries were given the nickname of “Marius’ Mules”. So if you are a former serviceman and wondered why you had to carry a 75lb pack and dig trenches everywhere you went, you get to blame Gaius Marius. The Romans were thus able to fortify themselves and defeat larger armies by constantly building forts, palisades, trenches, and towers, as well as keeping supplies handy. Although Roman forts were designed to be temporary, by the early Empire Roman they had largely pacified their territory. Cities that still exist today built up around legionary forts.
Unfortunately for the Romans, they were as good at fighting foreigners as they were themselves. Because funds for equipment, salary bonuses, and retirement land grants came from the generals rather than the state, very rich generals could in essence obtain private armies loyal to themselves rather than Rome. This led to the civil wars of the 1st centuries BC and AD, and the fall of the Roman Republic. Caesar and Pompey fought using the Marian model, and the emphasis on siege works and earthen works is littered throughout Caesar’s commentaries.
When the dust settled from the civil wars and Augustus became the first Roman Emperor, he reformed the legions further, mostly to prevent future civil wars. Augustus created a more fully state-backed military, helping ensure loyalty always went to the Emperor instead of the generals. In this he created a permanent, standing army of 28 legions. This switch from a citizen army to a fully professional one revolutionized the military in the West; in essence, it was the first modern army.
In order to achieve this, several changes to the form and makeup of the military were made. The first change altered the length of service for legionaries. Legions were previously mobilized yearly through levies and conscription, with legionaries serving for 6 years. Under Augustus, the army could be a full-time profession, and service was extended to 20 years. Legionaries could move up the ranks and make a career out of military service. Because of their service length, it meant Rome had a standing army of professional soldiers and veterans, as opposed to other states or the earlier Roman period of citizen armies. A more complex rank system based on experience was also now possible, and serves as the basis for a lot of modern military rank and promotion systems.
Further incentives, like a nice retirement package, citizenship for foreign legionaries, and a steady career meant Augustus could also draw largely from volunteers. These incentives helped create a new ability for upward social mobility through military service. Soldiering was a full time job.
Between Marius and Augustus, the concept of a standing, professional military force was born. Armies were previously annually conscripted forces of citizens who provided their own equipment, organized according to their socio-economic class. From the early Roman Empire on, the Roman legion was a permanent force of volunteers from throughout society, with standard government issued equipment and pay.
By today’s standards, things like standard equipment, professional training, and standing armies are par for the course. But these features of our modern militaries were features of Rome first, and gave rise to the concept of a professional fighting force.