This is a list of
Roman army
The Roman army () served ancient Rome and the Roman people, enduring through the Roman Kingdom (753–509 BC), the Roman Republic (509–27 BC), and the Roman Empire (27 BC–AD 1453), including the Western Roman Empire (collapsed Fall of the W ...
units and bureaucrats.
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Accensus'' – Light infantry men in the armies of the early Roman Republic, made up of the poorest men of the army.
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Actuarius
''Actuarius'' or ''actarius'', rendered in Greek as ''aktouarios'' (), was the title applied to officials of varying functions in the late Roman and Byzantine empires.
In the late Roman Empire, the ''actuarius'' was an official charged with the di ...
'' – A soldier charged with distributing pay and provisions.
*''Adiutor'' – A camp or headquarters adjutant or assistant.
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Aeneator'' – Military musician such as a bugler
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Agrimensor'' – A surveyor (a type of ''
immunes'').
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Antesignano'' – Supposedly a light infantry unit of legionaries who were used for protection of marching columns and to provide security to legions.
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Aquilifer
An ''aquilifer'' (, "eagle-bearer") was one of the '' signiferi'' in a Roman legion who carried the eagle standard of the legion. The name derives from the type of standard, '' aquila'', meaning "eagle" (which was the universal type used since 1 ...
'' – Bearer of the legionary eagle.
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Ala'' – a military formation composed of conscripts from the Italian military allies.
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Alaris'' – A cavalryman serving in an ''
ala''.
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Auxilia
The (; ) were introduced as non-citizen troops attached to the citizen Roman legion, legions by Augustus after his reorganisation of the Imperial Roman army from 27 BC. By the 2nd century, the contained the same number of infantry as the ...
'' – were introduced as non-citizen troops attached to the citizen legions by Augustus after his reorganisation of the Imperial Roman army from 30 BC.
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Architecti'' – An engineer or artillery constructor.
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Armicustos'' – A soldier tasked with the administration and supply of weapons and equipment. A quartermaster.
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Ballistarius'' – An artillery operator (a type of ''immunes'').
*''Beneficiarius'' – A soldier performing an extraordinary task such as military policing or a special assignment.
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Bucellarii
Bucellarii (the Latin plural of ''Bucellarius''; literally "biscuit–eater", ') were formations of escort troops used in the Roman Empire in Late Antiquity. They were employed by high-ranking military figures (such as Flavius Aetius and Belisari ...
'' – were formations of escort troops.
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Bucinator'' – A trumpeter or bugler.
*''Cacula'' – Servant or slave of a soldier.
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Capsarior'' – A medical orderly.
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Causarius'' – A soldier discharged for wounds or other medical reasons.
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Celeres
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The ''celeres'' (, ) were the bodyguard of the kings of Rome and the earliest cavalry unit in the Roman military.Livy, i. 15 (). Traditionally established by Romulus, the legendary founder and first King of Rome, the celeres comprised ...
'' - A royal guard created by Romulus to guard the King of Rome.
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Centurion
In the Roman army during classical antiquity, a centurion (; , . ; , or ), was a commander, nominally of a century (), a military unit originally consisting of 100 legionaries. The size of the century changed over time; from the 1st century BC ...
'' – Officer rank, generally one per 80 soldiers, in charge of a ''centuria''.
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Clinicus'' – A medic.
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Cohors amicorum
{{Italics title
''Cohors amicorum'' is a Latin term literally meaning "cohort of friends". The notion cohort is to be taken not in the strict, military sense (primarily the constitutive unit of a Roman legion; circa battalion), but indicated a fai ...
'' – Military staff company functioning as suite and bodyguard of a high Roman official.
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Comes
''Comes'' (plural ''comites''), translated as count, was a Roman title, generally linked to a comitatus or comital office.
The word ''comes'' originally meant "companion" or "follower", deriving from "''com-''" ("with") and "''ire''" ("go"). Th ...
'' – commanders of comitatenses.
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Comes stabuli
''Comes'' (plural ''comites''), translated as count, was a Roman title, generally linked to a comitatus or comital office.
The word ''comes'' originally meant "companion" or "follower", deriving from "''com-''" ("with") and "''ire''" ("go"). Th ...
'' – An office responsible for the horses and pack animals.
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Comitatenses
The ''comitatenses'' and later the '' palatini'' were the units of the field armies of the late Roman Empire. They were the soldiers that replaced the legionaries, who had formed the backbone of the Roman military since the late republic.
Org ...
'' – units of the field armies of the late empire. They were the soldiers that replaced the legionaries.
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Cornicen
A (: ) was a junior officer in the Roman army. The 's job was to signal salutes to officers and sound orders to the legions. The played the (making him an ). always marched at the head of the centuries, with the tesserarius, tesserary and t ...
'' – A bugler.
*''
Doctor
Doctor, Doctors, The Doctor or The Doctors may refer to:
Titles and occupations
* Physician, a medical practitioner
* Doctor (title), an academic title for the holder of a doctoral-level degree
** Doctorate
** List of doctoral degrees awarded b ...
'' – A trainer, subdivisions for everything from weapons to horn blowing.
*''
Draconarius
The draconarius was a type of '' signifer'' who bore a cavalry standard known as a '' draco'' in the Roman army.
Name
Strictly speaking, the word ''draconarius'' denotes the bearer of the military standard on which a dragon was represented. ...
'' – Bearer of a cavalry standard.
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Decurion'' – Leader of a troop of cavalry (14-30 men). Often confused with ''decanus''.
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Decanus
''Decanus'' means "chief of ten" in Late Latin. The term originated in the Roman army and became used thereafter for Subaltern (military), subaltern officials in the Byzantine Empire, as well as for various positions in the Church, whence derives ...
'' – Leader of a ''contubernium'' (a legionary tent group of 8 men).
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Discens'' – ''Miles'' in training for an ''immunis'' position.
*''
Duplarius'' – A soldier issued double pay, such as an
Optio
In a Roman army an (, from , 'to choose', so-called because superior officers chose the ; : ) held a rank in a (century) similar to that of an executive officer. The main function of an was as an , the second-in-command of a century, alth ...
or a minor cavalry officer as part of a
Turma
A ''turma'' (; plural ''turmae''; ) was a cavalry unit in the Roman army of the Republic and Empire. In the Byzantine Empire, it became applied to the larger, regiment-sized military-administrative divisions of a '' thema''. The word is often tran ...
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Dux'' – A general in charge of two or more legions. In the Third Century AD, an officer with a regional command transcending provincial boundaries, responsible directly to the emperor alone, usually appointed on a temporary basis in a grave emergency. In the fourth century AD, an officer in charge of a section of the frontier answering to the ''
Magister Militum
(Latin for "master of soldiers"; : ) was a top-level military command used in the late Roman Empire, dating from the reign of Constantine the Great. The term referred to the senior military officer (equivalent to a war theatre commander, the e ...
''.
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Duumviri navales'' – Two men elected to equip and repair the
Roman navy
The naval forces of the Ancient Rome, ancient Roman state () were instrumental in the Roman conquest of the Mediterranean Basin, but it never enjoyed the prestige of the Roman legions. Throughout their history, the Romans remained a primarily land ...
.
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Equites singulares Augusti'' – Elite cavalry unit tasked to guard the Roman Emperors. Usually commanded by a ''tribunus'' of praetorian rank.
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Evocatus
An ''evocatus'' (: ''evocati'') was a soldier in the Ancient Roman army who had served out his time and obtained an honorable discharge (''honesta missio'') but had voluntarily enlisted again at the invitation of the Roman consul, consul or othe ...
'' – A soldier who had served out his time and obtained his discharge (''missio''), but had voluntarily enlisted again at the invitation of the consul or other commander.
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Evocatus Augusti'' –
Praetorian Guard
The Praetorian Guard (Latin language, Latin: ''cohortes praetoriae'') was the imperial guard of the Imperial Roman army that served various roles for the Roman emperor including being a bodyguard unit, counterintelligence, crowd control and ga ...
who had served out his time and obtained his discharge (''missio''), but had voluntarily enlisted again.
*''
Equites
The (; , though sometimes referred to as " knights" in English) constituted the second of the property/social-based classes of ancient Rome, ranking below the senatorial class. A member of the equestrian order was known as an ().
Descript ...
'' –
Roman cavalry
Roman cavalry (Latin: ''equites Romani'') refers to the horse-mounted forces of the Roman army throughout the regal, republican, and imperial eras.
In the regal era, the Roman cavalry was a group of 300 soldiers called ''celeres'', tasked wi ...
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Foederati
''Foederati'' ( ; singular: ''foederatus'' ) were peoples and cities bound by a treaty, known as ''foedus'', with Rome. During the Roman Republic, the term identified the '' socii'', but during the Roman Empire, it was used to describe foreign ...
'' – For groups of "barbarian" mercenaries of various sizes who were typically allowed to settle within the empire.
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Frumentarii
The ''frumentarii'' were an ancient Roman military and secret police organization used as an intelligence agency. They began their history as a courier service and developed into an imperial spying agency. Their organization would also carry o ...
'' – Officials of the Roman Empire during the 2nd and 3rd era. Often used as a
Secret Service
A secret service is a government agency, intelligence agency, or the activities of a government agency, concerned with the gathering of intelligence data. The tasks and powers of a secret service can vary greatly from one country to another. For i ...
, mostly operating in uniform.
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Hastatus'' – The youngest of the heavy infantry in the pre-Marian armies, who were less well-equipped than the older ''Principes'' and ''Triarii''. These formed the first line of battle in front of the ''Principes''.
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Hastatus Prior'' – A centurion commanding a ''manipulus'' or ''centuria'' of ''hastati''. A high-ranking officer within a ''manipulus'' or ''centuria''.
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Hastatus Posterior'' – A deputy to the ''hastatus prior''
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Hastiliarius'' – A weapons instructor.
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Imaginifer'' – A standard-bearer carrying the imago – the standard which bore a likeness of the emperor, and, at later dates, his family.
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Immunes'' – Soldiers who were "immune" from combat duty and fatigues through having a more specialist role within the army.
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Jovians and Herculians'' – A senior palatine units
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Katepano
The ''katepánō'' (, ) was a senior Byzantine military rank and office. The word was Latinized as ''capetanus/catepan'', and its meaning seems to have merged with that of the Italian "capitaneus" (which derives from the Latin word "caput", mean ...
'' – A Byzantine military rank or military official.
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Laeti'' – was a term used in the late empire to denote communities of foreigners permitted to settle on, and granted land in, imperial territory on condition that they provide recruits for the Roman military.
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Legatus legionis'' – A legion commander of senatorial rank; literally the "deputy" of the emperor, who was the titular commander-in-chief.
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Limitanei
The ''limitanei'' (Latin, also called ''ripenses''), meaning respectively "the soldiers in frontier districts" (from the Latin word '' limes'' meaning frontier) or "the soldiers on the riverbank" (from the Rhine and Danube), were an important par ...
'' – A unit of frontier districts.
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Legatus pro praetore'' – Provincial governor of senatorial rank with multiple legions under his command.
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Legionary
The Roman legionary (in Latin ''legionarius''; : ''legionarii'') was a citizen soldier of the Roman army. These soldiers would conquer and defend the territories of ancient Rome during the Republic and Principate eras, alongside auxiliary and c ...
'' – The heavy infantry that was the basic military force of the ancient Roman army in the period of the late Roman Republic and the early Roman Empire.
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Magister militum
(Latin for "master of soldiers"; : ) was a top-level military command used in the late Roman Empire, dating from the reign of Constantine the Great. The term referred to the senior military officer (equivalent to a war theatre commander, the e ...
'' - High ranked commander in the
late Roman Empire
In historiography, the Late or Later Roman Empire, traditionally covering the period from 284 CE to 641 CE, was a time of significant transformation in Roman governance, society, and religion. Diocletian's reforms, including the establishment of t ...
. Equivalent of a general.
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Medicus'' – Physician or combat medic. Specializations included surgery (''medicus vulnerarius''), ophthalmology (''medicus ocularius''), and also veterinary (''medicus
veterinarius''). At least some held rank equivalent to a
centurion
In the Roman army during classical antiquity, a centurion (; , . ; , or ), was a commander, nominally of a century (), a military unit originally consisting of 100 legionaries. The size of the century changed over time; from the 1st century BC ...
.
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Megas doux'' –
Commander-in-chief of the
Byzantine navy
The Byzantine navy was the Navy, naval force of the Byzantine Empire. Like the state it served, it was a direct continuation from its Roman navy, Roman predecessor, but played a far greater role in the defence and survival of the state than its ...
.
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Miles'' or ''Miles Gregarius'' – The basic private level foot soldier.
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Numerus'' – A unit of foreign allies not integrated into the regular army structure. Later, a unit of border forces.
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Numerus Batavorum
The Numerus Batavorum, also called the cohors Germanorum,Suetonius, ''Galba' Germani corporis custodes, Germani corpore custodes, Imperial German Bodyguard or Germanic bodyguard, was a personal, imperial guards unit for the Roman emperors of ...
'' – was a personal, imperial guards unit for the Roman emperors of the Julio-Claudian dynasty (30 BC – AD 68) composed of Germanic soldiers.
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Optio
In a Roman army an (, from , 'to choose', so-called because superior officers chose the ; : ) held a rank in a (century) similar to that of an executive officer. The main function of an was as an , the second-in-command of a century, alth ...
'' – One per century as second-in-command to the centurion. Could also fill several other specialized roles on an ''ad hoc'' basis.
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Palatini'' – were elite units of the late army.
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Pedites'' – The infantry of the early army of the Roman kingdom. The majority of the army in this period.
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Peditatus'' – A term referring to any infantryman in the Roman Empire.
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Pilus Prior'' – Senior centurion of a cohort.
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Pilus Posterior'' – Deputy to the ''pilus prior''.
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Praefectus Castrorum
The ''praefectus castrorum'' ("camp prefect") was, in the Roman army of the early Empire, the third most senior staff officer of the Roman legion after the legate ('' legatus'') and the senior military tribune (''tribunus laticlavius''), both of ...
'' – Camp prefect, third-in-command of the legion, also responsible for maintaining the camp, equipment, and supplies. Usually a former ''primus pilus''.
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Praefectus Cohortis'' - Commander of a cohort.
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Praefectus legionis agens vice legati'' – Equestrian officer given the command of a legion in the absence of a senatorial ''legatus''. After the removal of senators from military command, the title of a legionary commander. ("''...agens vice legati'', dropped in later Third Century")
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Praetorians'' – A special force of bodyguards used by Roman Emperors.
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Praetorian prefect
The praetorian prefect (; ) was a high office in the Roman Empire. Originating as the commander of the Praetorian Guard, the office gradually acquired extensive legal and administrative functions, with its holders becoming the Emperor's chief ai ...
'' – Commander of the Praetorians.
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Primani'' – was a legio palatina, active in the 4th and 5th century.
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Primicerius
The Latin term ''primicerius'', Hellenized as ''primikērios'' (), was a title applied in the later Roman Empire and the Byzantine Empire to the heads of administrative departments, and also used by the Church to denote the heads of various colleg ...
'' – was a rank junior to the tribunus and senior to the senator.
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Primus Ordinis'' – The commanding officer of each ''centuria'' in the first cohort with the exception of the first ''centuria'' of the cohort.
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Primus Pilus
The ''primus pilus'' ( "first maniple of triarii") or ''primipilus'' was the senior centurion of the first cohort in a Roman legion, a formation of five double-strength centuries of 160 men each; he was a career soldier and advisor to the l ...
'' (literally 'first file' ) – The centurion commanding the first cohort and the senior centurion of the entire Legion.
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Princeps
''Princeps'' (plural: ''Principes'') is a Latin word meaning "first in time or order; the first, foremost, chief, the most eminent, distinguished, or noble; the first person". As a title, ''Princeps'' originated in the Roman Republic wherein the ...
'' – Pre-Marian soldier, initially equipped with the ''Hasta'' spear, but later with the ''pilum'', these men formed the second line of battle behind the ''Hastati'' in the pre-Marian armies. They were also chieftains in Briton like Dumnorix of the Regneses (he was killed by Gaius Salvius Liberalis' soldiers).
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Princeps Prior'' – A centurion commanding a ''century'' of ''principes''.
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Princeps Posterior'' – A deputy to the ''princeps prior''.
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Principales'' – A group of ranks, including ''aquilifer'', ''signifer'', ''optio'', and ''tesserarius''. Similar to modern NCOs (
Non-commissioned officer
A non-commissioned officer (NCO) is an enlisted rank, enlisted leader, petty officer, or in some cases warrant officer, who does not hold a Commission (document), commission. Non-commissioned officers usually earn their position of authority b ...
s).
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Protectores Augusti Nostri'' ( ''Protectores Divini Lateris'') – Honorific title for senior officers singled out for their loyalty to the Emperor and soldierly qualities. The ''protectores'' were an order of honor rather than a military unit. The order first appeared in the mid-200s AD.
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Quaestionarius'' – An interrogator or torturer.
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Retentus'' – A soldier kept in service after serving required term.
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Rorarii'' – The final line, or reserve, in the ancient pre-Marius Roman army. These were removed even before the so-called "Marian reforms", as the ''Triarii'' provided a very sturdy anchor.
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Sagittarii'' – Archers, including horse-riding auxiliary archers recruited mainly in North Africa, Balkans, and later the Eastern Empire.
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Salararius'' – A soldier enjoying special service conditions or hired as a mercenary.
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Scholae'' – was used in the late Roman Empire to signify a unit of Imperial Guards.
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Scholae Palatinae'' – An elite troop of soldiers created by the Emperor Constantine the Great to provide personal protection of the Emperor and his immediate family.
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Scorpionarius'' – An artilleryman operating a ''
scorpio'' artillery piece.
*''Sesquiplicarii'' – A soldier issued one-and-a-half times pay, such as a
Tesserarius
A ''tesserarius'' (, from ''tessera'', a small tile or block of wood on which watchwords were written) was a watch commander in the Roman army. They organized and had command over the nightly guard assigned to keep watch over the fort when in gar ...
or a minor cavalry officer as part of a
Turma
A ''turma'' (; plural ''turmae''; ) was a cavalry unit in the Roman army of the Republic and Empire. In the Byzantine Empire, it became applied to the larger, regiment-sized military-administrative divisions of a '' thema''. The word is often tran ...
*''
Signifer
A ''signifer'' () was a standard bearer of the Roman legions. He carried a ''signum'' ( standard) for a cohort or century. Each century had a ''signifer'' so there were 60 in a legion. Within each cohort, the first century's ''signifer'' woul ...
'' – Standard bearer of the Roman Legion.
*''Simplares'' - A soldier paid standard pay; a regular legionaire or somebody paid the equivalent
*''
Socii
The ''socii'' ( ) or ''foederati'' ( ) were confederates of ancient Rome, Rome and formed one of the three legal denominations in Roman Italy (''Italia'') along with the core Roman citizens (''Cives Romani'') and the extended ''Latin Rights, Lat ...
'' – Troops from allied states in the pre-Marian army before the
Social War (91–88 BC) Social War may refer to:
* Social War (357–355 BC), or the War of the Allies, fought between the Second Athenian Empire and the allies of Chios, Rhodes, and Cos as well as Byzantium
* Social War (220–217 BC), fought among the southern Greek sta ...
*
''Speculatores'' and ''Exploratores'' – The scouts and reconnaissance element of the Roman army.
*''
Supernumerarii'' – Supernumerary soldiers who served to fill the places of those who were killed or disabled by their wounds. Also used for the cavalry contingent of a legion during the
Principate
The Principate was the form of imperial government of the Roman Empire from the beginning of the reign of Augustus in 27 BC to the end of the Crisis of the Third Century in AD 284, after which it evolved into the Dominate. The principate was ch ...
, who despite being included on the cohort lists, camped separate to the infantry.
*''
Strategos
''Strategos'' (), also known by its Linguistic Latinisation, Latinized form ''strategus'', is a Greek language, Greek term to mean 'military General officer, general'. In the Hellenistic world and in the Byzantine Empire, the term was also use ...
'' - General and military governor of a
theme
Theme or themes may refer to:
* Theme (Byzantine district), an administrative district in the Byzantine Empire governed by a Strategos
* Theme (computing), a custom graphical appearance for certain software.
* Theme (linguistics), topic
* Theme ( ...
in the
Byzantine Empire
The Byzantine Empire, also known as the Eastern Roman Empire, was the continuation of the Roman Empire centred on Constantinople during late antiquity and the Middle Ages. Having survived History of the Roman Empire, the events that caused the ...
.
*''
Stratelates
''Stratēlatēs'' (, "driver/leader of the army") was a Greek term designating a general, which also became an honorary dignity in the Byzantine Empire. In the former sense, it was often applied to military saints, such as Theodore Stratelates.
...
'' – A Greek translation for the rank of ''magister militum'' that was used in the late Roman and Byzantine armies.
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Stratopedarches'' – A term originally used to refer to a Roman camp prefect, it was later used for a Roman or Byzantine general or a Byzantine commander-in-chief.
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Tablifer'' – A standard-bearer for the guard cavalry.
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Tesserarius
A ''tesserarius'' (, from ''tessera'', a small tile or block of wood on which watchwords were written) was a watch commander in the Roman army. They organized and had command over the nightly guard assigned to keep watch over the fort when in gar ...
'' – Guard commander, one per ''centuria''.
*''
Tirones'' – A basic trainee.
*''Torquati'' - A soldier issued with a golden collar in reward for bravery or valor. Depending on circumstances, they may also be rewarded with double pay, making them ''Torquato
Duplares''
*''
Triarii
''Triarii'' (: ''triarius'') ("the third liners") were one of the elements of the early Roman military manipular legions of the early Roman Republic (509 BC – 107 BC). They were the oldest and among the wealthiest men in the army and could a ...
'' – Spearmen of the pre-Marian armies, equipped with the Hasta, who formed the third line of battle behind the ''Principes''.
*''
Tribuni angusticlavii'' – Military tribune of equestrian rank, five of whom were assigned to each legion.
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Tribunus militum
A military tribune () was an officer of the Roman army who ranked below the legate and above the centurion. Young men of Equestrian rank often served as military tribunes as a stepping stone to the Senate. The should not be confused with the ...
'' - Officer in the Roman army who ranked below the legate but above the centurion.
*''
Tribunus militum laticlavius'' – Military tribune of senatorial rank. Second in command of a legion. Appointments to this rank seem to have ceased during the sole reign of
Gallienus
Publius Licinius Egnatius Gallienus (; – September 268) was Roman emperor with his father Valerian from 253 to 260 and alone from 260 to 268. He ruled during the Crisis of the Third Century that nearly caused the collapse of the empire. He ...
as part of a policy of excluding senators from military commands.
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Tubicen'' – A trumpeter.
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Urbanae'' – A special police force of Rome, created to counterbalance the Praetorians.
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Velites
''Velites'' (; : ) were a class of infantry in the Roman army of the mid-Republic from 211 to 107 BC. ''Velites'' were light infantry and skirmishers armed with javelins (), each with a 75cm (30 inch) wooden shaft the diameter of a finger, with ...
'' – A class of light infantry in the army of the Roman Republic.
*''
Venator'' – A hunter (a type of ''
immunes'').
*''
Vexillarius'' – Bearer of a ''
vexillum
The ''vexillum'' (; : ''vexilla'') was a flag-like object used as a War flag, military standard by units in the Roman army. A common ''vexillum'' displayed imagery of the Aquila (Roman), Roman ''aquila'' on a reddish backdrop.
Use in Roman arm ...
'' (standard).
*''
Vigiles
''Vigiles'' or more properly the ''Vigiles Urbani'' ("watchmen of the Rome, City") or ''Cohortes Vigilum'' ("Cohort (military unit), cohorts of the watchmen") were the firefighters and police of ancient Rome.
History
The ''triumviri, triumviri ...
'' – were the firefighters and police.
Sub-units of the Roman legion
Before the so-called "
Marian reforms
The Marian reforms were putative changes to the composition and operation of the Roman army during the late Roman Republic usually attributed to Gaius Marius (a general who was consul in 107, 104–100, and 86 BC). The most important of ...
", the structure of the legions was as follows:
*''
Contubernium
In ancient Rome, ''contubernium'' was a quasi-marital relationship between two Slavery in ancient Rome, slaves or between a slave (''Slavery in ancient Rome#The slave in Roman law and society, servus'') and a free person who was usually a form ...
'' – The smallest organized unit of soldiers in the Roman Army. It was composed of ten legionaries led by a ''
decanus
''Decanus'' means "chief of ten" in Late Latin. The term originated in the Roman army and became used thereafter for Subaltern (military), subaltern officials in the Byzantine Empire, as well as for various positions in the Church, whence derives ...
''. When on the march a Legion would often march ''contubernium''-abreast (8-abreast plus 2 support). In the Imperial Legion, ten ''contubernia'' formed a ''centuria''.
*
Maniple (''Manipulus'') – The pre-Marian sub-unit of the Roman Legions, consisting of 120 men (60 for the ''Triarii'').
*
''Legio'' (Republic) – A legion in the pre-Marian armies consisted of 60 ''manipuli'' of infantry and 10 ''turmae'' of cavalry. By 250 BC, there would be four Legions, two commanded by each Consul: two Roman legions which would be accompanied by an additional two allied Legions of similar strength and structure. For every Roman Legion there would be an allied Legion.
*''
Turma
A ''turma'' (; plural ''turmae''; ) was a cavalry unit in the Roman army of the Republic and Empire. In the Byzantine Empire, it became applied to the larger, regiment-sized military-administrative divisions of a '' thema''. The word is often tran ...
'' – A unit of cavalry in the pre-Marian army, which usually consisted of 32 horsemen.
After the consulships of Gaius Marius, the organisation of the legions would standardise as follows:
*''
Contubernium
In ancient Rome, ''contubernium'' was a quasi-marital relationship between two Slavery in ancient Rome, slaves or between a slave (''Slavery in ancient Rome#The slave in Roman law and society, servus'') and a free person who was usually a form ...
'' – The smallest organized unit of soldiers in the Roman Army. It was composed of ten legionaries (8 combat and 2 support) led by a ''
decanus
''Decanus'' means "chief of ten" in Late Latin. The term originated in the Roman army and became used thereafter for Subaltern (military), subaltern officials in the Byzantine Empire, as well as for various positions in the Church, whence derives ...
''. Ten ''contubernia'' formed a ''centuria''.
*''
Centuria
''Centuria'' (; : ''centuriae'') is a Latin term (from the stem ''centum'' meaning one hundred) denoting military units originally consisting of 100 men. The size of the centuria changed over time, and from the first century BC through most of ...
'' – 100 men under the command of a ''
centurion
In the Roman army during classical antiquity, a centurion (; , . ; , or ), was a commander, nominally of a century (), a military unit originally consisting of 100 legionaries. The size of the century changed over time; from the 1st century BC ...
'' and his ''
optio
In a Roman army an (, from , 'to choose', so-called because superior officers chose the ; : ) held a rank in a (century) similar to that of an executive officer. The main function of an was as an , the second-in-command of a century, alth ...
''. Six ''centuriae'' formed a ''cohors''.
*
''Cohors'' (cohort) – A ''cohors'' consisted of 600 men. The most senior ranking ''centurion'' of the six ''centuriae'' commanded the entire ''cohors''.
*First Cohort (''Cohors Prima'') – The first cohort was a double strength cohort (consisting of five double-strength ''centuriae''), numbering 800 men (excluding officers). The centurion of its first ''centuria'', the ''
Primus Pilus
The ''primus pilus'' ( "first maniple of triarii") or ''primipilus'' was the senior centurion of the first cohort in a Roman legion, a formation of five double-strength centuries of 160 men each; he was a career soldier and advisor to the l ...
'', commanded the first cohort and was also the most senior centurion in the legion.
*
''Legio'' (Imperial) – A legion was composed of nine cohorts and one first cohort. The legion's overall commander was the ''
legatus legionis'', assisted by the ''
praefectus castrorum
The ''praefectus castrorum'' ("camp prefect") was, in the Roman army of the early Empire, the third most senior staff officer of the Roman legion after the legate ('' legatus'') and the senior military tribune (''tribunus laticlavius''), both of ...
'' and other senior officers.
*''
Vexillatio
A ''vexillatio'' (: ''vexillationes'') was a detachment of a Roman legion formed as a temporary task force created by the Roman army of the Principate. It was named from the standard carried by legionary detachments, the ''vexillum'' (: ''vexill ...
'' – A temporary task force of one or more ''centuriae'' detached from the legion for a specific purpose. A ''vexillatio'' was commanded by an officer appointed by the ''Legatus''.
References
{{Ancient Rome topics
Military units and formations of ancient Rome
Military ranks of ancient Rome
Late Roman military ranks