early Roman army (c. 500 BCE) was, like those of other contemporary city-states
influenced by Greek civilization, a citizen militia that practiced hoplite
tactics. It was small (the population of free men of military age was then
about 9,000) and organized in five classes (in parallel to the comitia
centuriata, the body of citizens organized politically), with three
providing hoplites and two providing light infantry. The early Roman army was
tactically limited and its stance during this period was essentially defensive.
By the 3rd century BCE, the Romans abandoned the hoplite
formation in favor of a more flexible system in which smaller groups of 120 (or
sometimes 60) men called maniples could maneuver more independently on
the battlefield. Thirty maniples arranged in three lines with supporting troops
constituted a legion, totaling between 4,000 and 5,000 men.
early Republican legion consisted of five sections, each of which was equipped
differently and had different places in formation: the three lines of manipular
heavy infantry (hastati, principes and triarii), a force
of light infantry (velites), and the cavalry (equites). With the
new organization came a new orientation toward the offensive and a much more
aggressive posture toward adjoining city-states.
nominal full strength, an early Republican legion included 4,000 to 5,000 men:
3,600 to 4,800 heavy infantry, several hundred light infantry, and several
hundred cavalrymen. Legions were often significantly understrength from
recruitment failures or following periods of active service due to accidents,
battle casualties, disease and desertion. During the Civil War, Pompey's
legions in the east were at full strength because they were recently recruited,
while Caesar's legions were often well below nominal strength after long active
service in Gaul. This pattern also held true for auxiliary forces.
Until the late Republican period, the typical legionary was a
property-owning citizen farmer from a rural area (an adsiduus) who
served for particular (often annual) campaigns, and who supplied his own
equipment and, in the case of equites, his own mount. Harris suggests
that down to 200 BCE, the average rural farmer (who survived) might participate
in six or seven campaigns. Freedmen and slaves (wherever resident) and urban
citizens did not serve except in rare emergencies.
200 BCE, economic conditions in rural areas deteriorated as manpower needs
increased, so that the property qualifications for service were gradually
reduced. Beginning with Gaius Marius in 107 BCE, citizens without property and
some urban-dwelling citizens (proletarii) were enlisted and provided
with equipment, although most legionaries continued to come from rural areas.
Terms of service became continuous and long—up to twenty years if emergencies
required it although Brunt argues that six- or seven-year terms were more
in the 3rd century BCE, legionaries were paid stipendium (amounts are
disputed but Caesar famously "doubled" payments to his troops to 225 denarii
a year), could anticipate booty and donatives (distributions of plunder by
commanders) from successful campaigns and, beginning at the time of Marius,
often were granted allotments of land upon retirement. Cavalry and light
infantry attached to a legion (the auxilia) were often recruited in the
areas where the legion served. Caesar formed a legion, the Fifth Alaudae, from
non-citizens in Transalpine Gaul to serve in his campaigns in Gaul. By the time
of Caesar Augustus, the ideal of the citizen-soldier had been abandoned and the
legions had become fully professional. Legionaries received 900 sesterces
a year and could expect 12,000 sesterces on retirement.
end of the Civil War, Augustus reorganized Roman military forces, discharging
soldiers and disbanding legions. He retained 28 legions, distributed through
the provinces of the Empire. During the Principate, the tactical organization
of the Army continued to evolve. The auxilia remained independent
cohorts, and legionary troops often operated as groups of cohorts rather than
as full legions. A new versatile type of unit - the cohortes equitatae –
combined cavalry and legionaries in a single formation. They could be stationed
at garrisons or outposts and could fight on their own as balanced small forces
or combine with other similar units as a larger legion-sized force. This
increase in organizational flexibility helped ensure the long-term success of
Roman military forces.
Emperor Gallienus (253–268 CE) began a reorganization that created the last
military structure of the late Empire. Withdrawing some legionaries from the
fixed bases on the border, Gallienus created mobile forces (the Comitatenses
or field armies) and stationed them behind and at some distance from the
borders as a strategic reserve. The border troops (limitanei) stationed
at fixed bases continued to be the first line of defense. The basic unit of the
field army was the "regiment", legiones or auxilia for
infantry and vexellationes for cavalry. Evidence suggests that nominal
strengths may have been 1,200 men for infantry regiments and 600 for cavalry,
although many records show lower actual troop levels (800 and 400).
infantry and cavalry regiments operated in pairs under the command of a comes.
In addition to Roman troops, the field armies included regiments of
"barbarians" recruited from allied tribes and known as foederati.
By 400 CE, foederati regiments had become permanently established units
of the Roman army, paid and equipped by the Empire, led by a Roman tribune and
used just as Roman units were used. In addition to the foederati, the
Empire also used groups of barbarians to fight along with the legions as
"allies" without integration into the field armies. Under the command
of the senior Roman general present, they were led at lower levels by their own
leadership evolved greatly over the course of the history of Rome. Under the
monarchy, the hoplite armies were led by the kings of Rome. During the early
and middle Roman Republic, military forces were under the command of one of the
two elected consuls for the year. During the later Republic, members of the
Roman Senatorial elite, as part of the normal sequence of elected public
offices known as the cursus honorum, would have served first as quaestor
(often posted as deputies to field commanders), then as praetor.
the end of a term as praetor or consul, a Senator might be appointed by the
Senate as a propraetor or proconsul (depending on the highest
office held before) to govern a foreign province. More junior officers (down to
but not including the level of centurion) were selected by their commanders
from their own clientelae or those recommended by political allies among
the Senatorial elite.
Under Augustus, whose most important political priority was to
place the military under a permanent and unitary command, the Emperor was the
legal commander of each legion but exercised that command through a legatus
(legate) he appointed from the Senatorial elite. In a province with a single
legion, the legate commanded the legion (legatus legionis) and also
served as provincial governor, while in a province with more than one legion, each
legion was commanded by a legate and the legates were commanded by the
provincial governor (also a legate but of higher rank).
the later stages of the Imperial period (beginning perhaps with Diocletian),
the Augustan model was abandoned. Provincial governors were stripped of
military authority, and command of the armies in a group of provinces was given
to generals (duces) appointed by the Emperor. These were no longer
members of the Roman elite but men who came up through the ranks and had seen
much practical soldiering. With increasing frequency, these men attempted
(sometimes successfully) to usurp the positions of the Emperors who had
appointed them. Decreased resources, increasing political chaos and civil war
eventually left the Western Empire vulnerable to attack and takeover by
neighboring barbarian peoples.
is known about the Roman navy than the Roman army. Prior to the middle of the
3rd century BC, officials known as duumviri navales commanded a fleet of
twenty ships used mainly to control piracy. This fleet was given up in 278 BCE
and replaced by allied forces. The First Punic War required that Rome build
large fleets, and it did so largely with the assistance of and financing from allies.
This reliance on allies continued to the end of the Roman Republic. The quinquereme
was the main warship on both sides of the Punic Wars and remained the mainstay
of Roman naval forces until replaced by the time of Caesar Augustus by lighter
and more maneuverable vessels.
compared with a trireme, the quinquereme permitted the use of a mix of
experienced and inexperienced crewmen (an advantage for a primarily land-based
power), and its lesser maneuverability permitted the Romans to adopt and perfect
boarding tactics using a troop of about 40 marines in lieu of the ram. Ships
were commanded by a navarch, a rank equal to a centurion, who was
usually not a citizen. Potter suggests that because the fleet was dominated by
non-Romans, the navy was considered non-Roman and allowed to atrophy in times
Information suggests that by the time of the late Empire (350 CE),
the Roman navy comprised several fleets including warships and merchant vessels
for transportation and supply. Warships were oared sailing galleys with three
to five banks of oarsmen. Fleet bases included such ports as Ravenna, Arles,
Aquilea, Misenum and the mouth of the Somme River in the West and Alexandria
and Rhodes in the East. Flotillas of small river craft (classes) were
part of the limitanei (border troops) during this period, based at
fortified river harbors along the Rhine and the Danube. That prominent generals
commanded both armies and fleets suggests that naval forces were treated as
auxiliaries to the army and not as an independent service. The details of
command structure and fleet strengths during this period are not well known,
although fleets were commanded by prefects.