Recruitment, Training and Funding of the Imperial Military

A permanent military serving the emperors

After the civil wars of the first century BC, Augustus brought previously opposing legions under his control. The Imperial army was a professional force whose soldiers served for many years, rather than simply assembling for a single campaign. Maintaining it required a continuing supply of recruits, regular pay and military training.

The navy also became a permanent part of Imperial military power. Augustus established fleets at Misenum, near Naples, and Ravenna. Naval forces helped transport and supply the army and respond to military needs across the empire. Their crews needed military discipline as well as the skills to operate ships.

Recruiting legionaries and auxiliaries

A legionary was a soldier serving in a Roman legion. In the early Imperial period, recruits had to be Roman citizens. Citizenship was a legal status, not simply a description of someone living inside the empire: many provincial inhabitants did not possess it.

From Augustus onwards, legionary recruitment was largely voluntary. However, emperors could use conscription, or compulsory recruitment, when an emergency demanded many more men. The Illyrian revolt of AD 6–9, for example, created exceptional pressure to recruit.

Legionaries did not all come from Italy. As legions became established in provincial bases, increasing numbers of recruits came from outside Italy. Long-standing military communities, including the families of veterans, provided potential recruits.

The auxiliaries were soldiers in supporting regiments supplying infantry and cavalry. During the first century AD, most were recruited from non-citizen inhabitants of the empire. Early recruitment combined volunteers with compulsory levies; from the Flavian period, beginning in AD 69, recruitment became largely voluntary, although emergencies could still bring conscription.

An important incentive for non-citizens to enlist was the award of Roman citizenship on discharge, normally after 25 years of auxiliary service. Service therefore offered a route to a new legal status as well as regular pay. The citizen descendants of auxiliary veterans could subsequently enter the legions, helping to widen the pool of eligible legionary recruits. Others chose to serve in their fathers’ auxiliary regiments instead.

An auxiliary regiment might initially recruit from the people whose name it bore. Later, many recruited near their current base, so a unit’s traditional name did not necessarily reveal where its serving soldiers came from. The distinction based on citizenship also changed: the widespread grant of citizenship in AD 212 meant that auxiliary units thereafter recruited predominantly citizens.

Recruiting and preparing naval crews

Naval crews were commonly recruited locally and from poorer people. The regular Imperial fleets used professional volunteer oarsmen, rather than depending on enslaved or convict rowers. Crews were military personnel, not merely civilian sailors: they were subject to Roman military law and could serve as light-armed troops on land when needed.

Crews could train in protected naval ports. Training made their collective effort effective: a ship manoeuvring under oars depended on coordinated work rather than the strength of isolated individuals. Rowers had to work together so that the vessel could move and turn as required. Discipline mattered because crews had to continue acting together amid the confusion and danger of battle. Naval preparation therefore connected ship-handling with the obedience expected of soldiers.

Building soldiers’ endurance and practical skills

Joining the army meant entering a demanding military routine. Recruits needed the fitness to travel with equipment, the skill to handle weapons and the discipline to act together.

The late fourth-century writer Vegetius collected earlier Roman military practices and recommended them as a basis for reform. His account helps explain Roman training methods, but it is not a record of an identical routine followed by every unit throughout the Imperial period.

Vegetius emphasised marching in step and in ranks, alongside running, jumping, swimming and carrying burdens. These exercises prepared recruits for the physical demands of campaigning. Marching practice also taught men to move together: a group of individually strong soldiers was less useful if it could not maintain its order.

Weapons training developed control as well as strength. Vegetius described practice with wicker shields against posts and recommended teaching soldiers to thrust with the point of a sword, rather than merely slash with its edge. Recruits also practised aiming and throwing missile weapons, handling shields, deflecting blows and parrying attacks. Repetition made these actions familiar before soldiers faced a real opponent.

Collective drill taught recruits to keep their ranks and the correct intervals between men. They also learned to dig trenches and plant palisades. Training therefore prepared them not only to fight but also to build the defences needed to protect an army on campaign.

Discipline and continuing military work

The optio, an officer assisting the centurion, had responsibilities for training, while the centurion maintained discipline. Obedience helped soldiers carry out instructions and cooperate even under pressure.

Discipline could be enforced through physical punishment: centurions could beat soldiers with vine canes. Military life also involved strenuous work beyond fighting, including digging earthworks and collecting timber. Training and discipline prepared men for service in which physical endurance and dependable cooperation were essential.

Paying for a standing army and navy

A permanent military cost money even when no major battle was taking place. The government had to support wages, provisions, equipment and military infrastructure; maintaining the navy also required ships and naval bases.

Tax revenues and rents collected by the imperial government financed military expenditure. The military absorbed a large share of government revenue, making it a major burden on the empire’s economy. Communities could also be required to supply goods, labour or services for military needs. Funding was therefore broader than simply giving soldiers coins: it involved obtaining the resources that kept forces supplied and operational.

Retirement payments had a specific funding arrangement. In AD 6, Augustus established the aerarium militare, a military treasury intended to provide discharge benefits for army veterans. He contributed 170 million sesterces of his own money, and client kings and cities also made contributions.

The fund received dedicated tax revenues, notably a 5% inheritance tax, with exemptions for immediate family inheritances and smaller estates, and a 1% tax on auction sales. This treasury should be distinguished from the revenues supporting ordinary military running costs: its particular purpose was veterans’ retirement payments.

Providing a dependable discharge benefit also served a political purpose. Veterans without secure support could become a source of unrest or depend on individual commanders for rewards. A state-supported payment aimed to make retirement more predictable and strengthen loyalty to the Imperial state.

Regular pay, bonuses and deductions

Soldiers received regular wages, called stipendium. Under Augustus, the basic legionary salary was 225 denarii a year. This was gross pay: deductions for food and equipment reduced the money a soldier could actually spend. Pay rose under later emperors, so the Augustan figure should not be applied to the whole Imperial period.

Emperors could also award donativa, additional bonus payments. These were distinct from regular wages and could help secure soldiers’ loyalty. Legionaries could receive a discharge payment at the end of service, making military employment a potential source of longer-term financial security as well as current income.

Auxiliary pay varied with period and role. Auxiliary infantrymen generally received less than legionaries in the early empire; cavalry rates could differ. Naval crews received pay comparable to auxiliary infantry. These payments supported recruitment, but military employment also brought serious dangers and hardships. Regular wages did not mean an easy or safe working life.