The Roman armies were the most highly organized and disciplined fighting forces of their time. These powerful legions enabled Rome to conquer neighboring and distant peoples, building an empire that spanned much of Europe and reached into Asia and northern Africa. When the conquered lands became part of the Roman empire, the armies defended Rome’s far-flung frontiers and maintained peace throughout the Roman world. Yet the significance of the Roman armies went far beyond their military role. When Roman soldiers traveled to distant parts of the empire, they carried with them Roman ideas, customs, and culture. After military service, many soldiers settled in these distant lands, forming colonies of Roman army veterans. As a result, the armies played an important role in the spread of Roman civilization.

Citizen-Soldiers of Early Rome. The earliest Roman armies consisted of Roman citizens who owned property. The Romans considered military service a basic responsibility of citizenship, and male citizens between ages 17 and 46 could be called to serve whenever Rome needed soldiers. They served until the crisis was over, and then returned to civilian life. During their years of eligibility, men served a maximum of 16 years as foot soldiers in the infantry or 10 years in the cavalry. Later military reforms changed the maximum amount of service to 20 and then 25 years.

Soldiers had to provide their own weapons and armor. The wealthiest citizens, who could afford horses and equipment, served in the cavalry. Those of lesser means did their military service in the infantry. The poorest citizens, who could not afford to equip themselves, often did not serve at all. Citizen-soldiers received only a small payment for their time and service. Their main income came from their farms or business interests. (Regular military pay was not introduced until 406 B.C.) Each soldier did receive an allotment, called a salarium, for the purchase of salt. The modern word salary is derived from the Latin salarium.

Rise of a Professional Army. In the early years of the Roman Republic, armies generally fought in areas near Rome. They regularly returned home after each campaign to attend to their property and businesses. However, beginning with the Punic Wars against Carthage, Roman armies often stayed abroad for a year or longer, and the citizen-soldiers became reluctant to serve.

In 107 B.C. the politician and army commander Gaius Marius had difficulty recruiting men who were willing to be away from home for long periods. He solved the problem by ending the property requirement for military service and opening the army to volunteers. Romans from the poorer classes flocked to join the armies, attracted by the possibility of long-term careers and booty* from overseas conquests. These new soldiers formed Rome’s first permanent, professional army.

The Roman Legions. Roman armies were composed of forces called legions. By 31 B.C., Rome had sixty legions. The emperor Augustus reduced the number of legions to twenty-eight, totaling about 300,000 men. Each legion had a name—referring to a province*, an emperor, or a god—and a number. If a legion was destroyed in battle, its name was never used again.

A standard legion contained 4,200 soldiers. It was made up of four types of infantry—triarii, the oldest legionnaires*; principes, the seasoned veterans; hastati, the younger soldiers; and velites, the youngest, poorest, and most lightly armed troops. Each of these groups was divided into units of 60 or 120 men called maniples, the basic fighting units of the army. Because of its size, the maniple could maneuver quickly in any type of terrain. Maniples were further divided into centuries. In later years, a unit called the cohort, containing 300 to 600 legionnaires, replaced the maniple as the basic unit within the legion. Each cohort contained two centuries, and ten cohorts made up a legion.

In addition to infantry, each legion included a cavalry of between 120 and 300 men. These mounted soldiers rarely fought in battle, serving primarily as scouts and messengers. Cavalries that did fight usually consisted of foreign troops. Each legion also had military engineers, surveyors, stonemasons, and other experts to select sites for army camps and to supervise the building of roads, defensive walls, forts, and bridges.

Overall command of the Roman armies was held by two consuls, civilian officials who served for one-year terms, which might be extended during emergencies. In time of war, one consul was chosen, often by lot, to lead a particular campaign. An army could also be commanded by a praetor*, if a consul was unavailable. Next in the chain of command were the legates, often members of the Roman Senate. A legate was someone to whom the commander might delegate some of his power.

* booty riches or property gained through conquest

* province overseas area controlled by Rome

* legionnaire member of a legion

* praetor Roman official, just below the consul in rank, in charge of judicial proceedings and of governing overseas provinces

Each legion was led by six tribunes, who rotated command daily so that no one officer became too powerful. Below the tribunes were the centurions, the backbone of the army. They were responsible for disciplining the soldiers. A large staff of clerks in each legion took care of keeping records, overseeing supplies, handling documents, and various other tasks.

Remember: Consult the index at the end of volume 4 to find more Information on many topics.

Foreign Troops. From the early days of the Republic, Rome made use of the armies of allied states to help defend its territories. These groups of non-Romans, known as the auxilia, or auxiliaries, generally patrolled distant frontiers and supported the legions in battle. The men who joined the auxiliaries were promised full Roman citizenship after 25 years of service.

The auxilia resembled legions in both organization and chain of command. Their infantry units were divided into cohorts, which in turn were divided into centuries. The commanding officers of the auxilia came both from Roman legions and from the ranks of the auxilia.

Some auxilia contained expert units, such as Syrian archers or Spanish cavalry, that made use of the special skills of particular peoples. The Roman legions often called on these expert auxiliary units for help.

The Praetorian Guard. During the Roman Republic, the principal commander of a legion often selected a group of soldiers to act as his private bodyguards. This guard was known as the praetorian cohort, after the praetorium—the commander’s tent. Following the model of the praetorian cohort, the emperor Augustus established a special force called the Praetorian Guard. These guards were charged with protecting the emperor and received better pay and benefits, and often better training, than ordinary soldiers.

Some soldiers of the Praetorian Guard were based in Rome, where they patrolled the imperial palaces and other major buildings. Others were stationed in towns around Rome. In time, this special force of between 4,500 and 9,000 men became a threat to imperial* power. Although the Praetorian Guard had no direct role in government, its members could force an emperor from power if he lost their support and loyalty. In A.D. 41, some members of the guard aided in the conspiracy to murder the emperor Caligula, and then placed his uncle Claudius on the throne. Later emperors weakened the guard by reducing its numbers and stationing its soldiers away from the imperial palace. Some emperors replaced the Praetorian Guard with individuals loyal to them. In the early A.D. 300s, the emperor Constantine I abolished the Praetorian Guard.

Training and Army Life. Intensive training and strict discipline gave Roman armies their great strength. Soldiers trained rigorously, marching and running long distances with heavy packs on their backs and practicing for many hours with their weapons. Discipline was very severe. Soldiers who broke rules were harshly punished.

Army camps, known as castra, were highly organized. The camps were laid out like cities, with parallel streets that formed a square or a rectangle. Located at the ends of the two main crossing streets were the four principal gates that were used to enter or leave the camp. The camp was surrounded by a ditch, and a palisade* was built on the excavated soil. Because all camps had the same layout, every soldier knew exactly where to pitch his tent and where to store horses, baggage, and supplies. Temporary camps could be taken down easily and moved quickly—important features when the army was on the move and needed to construct camp on a new site every day.

* imperial pertaining to an emperor or empire

* palisade wooden fence made of stakes or pointed sticks as a barrier against invaders

In time, Rome built more permanent camps and forts throughout the empire. These military bases defended the frontiers and sheltered local peoples in times of danger. They also attracted Roman traders and colonists, who established communities around the military bases and brought Roman civilization to remote regions. Several modern European cities grew around the sites of permanent Roman camps.

When Roman soldiers retired they received a payment and a plot of land, often in the province where they had served. Former soldiers who settled on these plots helped to populate the Roman provinces and to extend Roman culture and ideals to the far corners of the empire. Eventually, however, soldiers became a cause of instability in the Roman empire. As more and more foreign troops joined the Roman armies and served in distant provinces, their loyalty to Rome weakened, and Rome’s control of its provinces declined. (See also Armies, Greek; Naval Power, Roman; Wars and Warfare, Roman.)

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