This is a list of
Roman army
The Roman army (Latin: ) was the armed forces deployed by the Romans throughout the duration of Ancient Rome, from the Roman Kingdom (c. 500 BC) to the Roman Republic (500–31 BC) and the Roman Empire (31 BC–395 AD), and its medieval contin ...
units and bureaucrats.
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Accensus
The term ''accensi'' (Singular: ''accensus'') is applied to two different groups. Originally, the ''accensi'' were light infantry in the armies of the early Roman Republic. They were the poorest men in the legion, and could not afford much equipme ...
'' – 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'' – A military who served food.
*''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'' – 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 (, lit. "auxiliaries") were introduced as non-citizen troops attached to the citizen legions by Augustus after his reorganisation of the Imperial Roman army from 30 BC. By the 2nd century, the Auxilia contained the same number of in ...
'' – 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
Vitruvius (; c. 80–70 BC – after c. 15 BC) was a Roman architect and engineer during the 1st century BC, known for his multi-volume work entitled ''De architectura''. He originated the idea that all buildings should have three attribute ...
'' – 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
Ballistarius (plural ''ballistarii'') were infantrymen of the Roman army who handled ballistae. They were classed as immunes, exempt from fatigue duty of entrenching or building.
Notes
See also
* List of Roman army unit types
This is a lis ...
'' – 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'' – 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'' - A royal guard created by Romulus to guard the King of Rome.
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Centurion
A centurion (; la, centurio , . la, centuriones, label=none; grc-gre, κεντυρίων, kentyríōn, or ) was a position in the Roman army during classical antiquity, nominally the commander of a century (), a military unit of around 80 le ...
'' – 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'' – Military staff company functioning as suite and bodyguard of a high Roman official.
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Comes
''Comes'' ( ), plural ''comites'' ( ), was a Roman title or office, and the origin Latin form of the medieval and modern title "count".
Before becoming a word for various types of title or office, the word originally meant "companion", either i ...
'' – commanders of comitatenses.
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Comes stabuli'' – A 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 Marian reforms.
Organizat ...
'' – units of the field armies of the late empire. They were the soldiers that replaced the legionaries.
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Cornicen'' – A bugler.
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Doctor'' – A trainer, subdivisions for everything from weapons to horn blowing.
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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. T ...
'' – 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'' – Leader of a ''contubernium'' (a legionary tent group of 8 men).
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Discens'' – ''Miles'' in training for an ''immunis'' position.
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Duplarius Duplarius (plural ''duplares''), ''duplicarius'' or ''dupliciarius'', was an inferior, low-ranking Roman officer, who received double rations or increased payment valuing the 2nd ration based on their valor. As part of cavalry, one decurio, one dupl ...
'' – A soldier issued double pay, such as an
Optio
An , plural ( lat, italic=yes, optiō, , from , "to choose", so-called because an was chosen by a centurion), was a position in a '' centuria'' (century) of a Roman army similar to that of an executive officer. The main function of an was as ...
or a minor cavalry officer as part of a
Turma
*''
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", plural ) was a top-level military command used in the later Roman Empire, dating from the reign of Constantine the Great. The term referred to the senior military officer (equivalent to a war theatre commander, ...
''.
*''
Duumviri navales'' – Two men elected to equip and repair the
Roman navy
The naval forces of the ancient Roman state ( la, Classis, lit=fleet) 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 prim ...
.
*''
Equites singulares Augusti
The ''equites singulares Augusti'' (lit: "personal cavalry of the emperor" i.e. imperial horseguards) were the cavalry arm of the Praetorian Guard during the Principate period of imperial Rome. Based in Rome, they escorted the Roman emperor whenev ...
'' – Elite cavalry unit tasked to guard the Roman Emperors. Usually commanded by a ''tribunus'' of praetorian rank.
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Evocatus'' – 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: ''cohortēs praetōriae'') was a unit of the Imperial Roman army that served as personal bodyguards and intelligence agents for the Roman emperors. During the Roman Republic, the Praetorian Guard were an escort f ...
who had served out his time and obtained his discharge (''missio''), but had voluntarily enlisted again.
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Equites
The ''equites'' (; literally "horse-" or "cavalrymen", though sometimes referred to as "knights" in English) constituted the second of the property-based classes of ancient Rome, ranking below the senatorial class. A member of the equestrian ...
'' –
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 wit ...
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Foederati'' – For groups of "barbarian" mercenaries of various sizes who were typically allowed to settle within the empire.
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Frumentarii'' – Officials of the Roman Empire during the 2nd and 3rd era. Often used as a
Secret Service, 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
* the singular of hastati, a class of infantry in the armies of the early Roman Republic who originally fought as spearmen
Species Latin names
* A. hastatus
** ''Amphineurus hastatus'', Alexander, 1925, a crane fly species in the genus ''Amphineu ...
'' – A centurion commanding a ''manipulus'' or ''centuria'' of ''hastati''. A high-ranking officer within a ''manipulus'' or ''centuria''.
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Hastatus Posterior
* the singular of hastati, a class of infantry in the armies of the early Roman Republic who originally fought as spearmen
Species Latin names
* A. hastatus
** '' Amphineurus hastatus'', Alexander, 1925, a crane fly species in the genus '' Amph ...
'' – 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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Katepano
The ''katepánō'' ( el, κατεπάνω, lit. " he oneplaced at the top", or " the topmost") 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 th ...
'' – 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 ''legatus'' (; anglicised as legate) was a high-ranking Roman military officer in the Roman Army, equivalent to a modern high-ranking general officer. Initially used to delegate power, the term became formalised under Augustus as the office ...
'' – 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 ''līmitāneī'' (Latin, also called ''rīpēnsēs''), meaning respectively "the soldiers in frontier districts" (from the Latin phrase līmēs, meaning a military district of a frontier province) or "the soldiers on the riverbank" (from the ...
'' – 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'', plural ''legionarii'') was a professional heavy infantryman of the Roman army after the Marian reforms. These soldiers would conquer and defend the territories of ancient Rome during the late Republ ...
'' – 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", plural ) was a top-level military command used in the later Roman Empire, dating from the reign of Constantine the Great. The term referred to the senior military officer (equivalent to a war theatre commander, ...
'' - High ranked commander in the
late Roman Empire. Equivalent of a general.
*''
Medicus
Medicus is Latin for physician.
Medicus may also refer to:
People
* Dieter Medicus (1929–2015), German jurist
* Dieter Medicus (ice hockey) (born 1957), German ice hockey player
* Friedrich Kasimir Medikus (1738–1808), German physician and ...
'' – Physician or combat medic. Specializations included surgery (''medicus vulnerarius''), ophthalmology (''medicus ocularius''), and also veterinary (''medicus
veterinarius
A ''veterinarius'' was a soldier in the Roman army who served as a veterinary surgeon.
Their job was to care for the multitude of animals attached to an individual military unit: cavalry horses, beasts of burden, animals used for sacrifice or ani ...
''). At least some held rank equivalent to a
centurion
A centurion (; la, centurio , . la, centuriones, label=none; grc-gre, κεντυρίων, kentyríōn, or ) was a position in the Roman army during classical antiquity, nominally the commander of a century (), a military unit of around 80 le ...
.
*''
Megas doux'' –
Commander-in-chief of the
Byzantine navy
The Byzantine navy was the naval force of the East Roman or Byzantine Empire. Like the empire it served, it was a direct continuation from its Imperial Roman predecessor, but played a far greater role in the defence and survival of the state th ...
.
*''
Miles
The mile, sometimes the international mile or statute mile to distinguish it from other miles, is a British imperial unit and United States customary unit of distance; both are based on the older English unit of length equal to 5,280 English ...
'' or ''Miles Gregarius'' – The basic private level foot soldier.
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Numerus
Numerus (Latin: "number") may refer to one of the following
*Grammatical number
* Numerus, a military unit of the Roman army
The Roman army (Latin: ) was the armed forces deployed by the Romans throughout the duration of Ancient Rome, from th ...
'' – A unit of barbarian allies not integrated into the regular army structure. Later, a unit of border forces.
*''
Numerus Batavorum'' – 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
An , plural ( lat, italic=yes, optiō, , from , "to choose", so-called because an was chosen by a centurion), was a position in a '' centuria'' (century) of a Roman army similar to that of an executive officer. The main function of an was as ...
'' – 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
A pilus (Latin for 'hair'; plural: ''pili'') is a hair-like appendage found on the surface of many bacteria and archaea. The terms ''pilus'' and '' fimbria'' (Latin for 'fringe'; plural: ''fimbriae'') can be used interchangeably, although some r ...
'' – Senior centurion of a cohort.
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Pilus Posterior
A pilus (Latin for 'hair'; plural: ''pili'') is a hair-like appendage found on the surface of many bacteria and archaea. The terms ''pilus'' and '' fimbria'' (Latin for 'fringe'; plural: ''fimbriae'') can be used interchangeably, although some r ...
'' – Deputy to the ''pilus prior''.
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Praefectus Castrorum'' – 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
''Praefectus'', often with a further qualification, was the formal title of many, fairly low to high-ranking, military or civil officials in the Roman Empire, whose authority was not embodied in their person (as it was with elected Magistrates) but ...
'' - Commander of a cohort.
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Praefectus legionis agens vice legati
''Praefectus'', often with a further qualification, was the formal title of many, fairly low to high-ranking, military or civil officials in the Roman Empire, whose authority was not embodied in their person (as it was with elected Magistrates) but ...
'' – 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 ( la, praefectus praetorio, el, ) 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 be ...
'' – Commander of the Praetorians.
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Primicerius'' – was a rank junior to the tribunus and senior to the senator.
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Primus Ordinis
Primus (Latin, 'first') may refer to:
Arts, entertainment and media Fictional entities
* Primus (DC Comics), a character in the Omega Men team
* Primus (Marvel Comics), a character created by Arnim Zola
* Primus, a character in the novel '' Star ...
'' – The commanding officer of each ''centuria'' in the first cohort with the exception of the first ''centuria'' of the cohort.
*''
Primus Pilus'' (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 man, first person". As a title, ''princeps'' originated in the Roman Republic w ...
'' – 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
''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 man, first person". As a title, ''princeps'' originated in the Roman Republic w ...
'' – A deputy to the ''princeps prior''.
*''
Principales'' – A group of ranks, including ''aquilifer'', ''signifer'', ''optio'', and ''tesserarius''. Similar to modern NCOs (
Non-commissioned officer
A non-commissioned officer (NCO) is a military officer who has not pursued a commission. Non-commissioned officers usually earn their position of authority by promotion through the enlisted ranks. (Non-officers, which includes most or all enli ...
s).
*''
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.
*''
Quaestionarius'' – An interrogator or torturer.
*''
Retentus'' – A soldier kept in service after serving required term.
*''
Rorarii'' – The final line, or reserve, in the ancient pre-Marius Roman army. These were removed even before the Marian reforms, as the ''Triarii'' provided a very sturdy anchor.
*''
Sagittarii'' – Archers, including horse-riding auxiliary archers recruited mainly in North Africa, Balkans, and later the Eastern Empire.
*''
Salararius'' – A soldier enjoying special service conditions or hired as a mercenary.
*''
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 or a minor cavalry officer as part of a
Turma
*''
Signifer'' – Standard bearer of the Roman Legion.
*''Simplares'' - A soldier paid standard pay; a regular legionaire or somebody paid the equivalent
*''
Socii
The ''socii'' ( in English) or '' foederati'' ( in English) were confederates of Rome and formed one of the three legal denominations in Roman Italy (''Italia'') along with the Roman citizens (''Cives'') and the '' Latini''. The ''Latini'', who ...
'' – 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 s ...
*
''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 is the name sometimes given to the first period 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 so-called Dominate ...
, who despite being included on the cohort lists, camped separate to the infantry.
*''
Strategos
''Strategos'', plural ''strategoi'', Latinized ''strategus'', ( el, στρατηγός, pl. στρατηγοί; Doric Greek: στραταγός, ''stratagos''; meaning "army leader") is used in Greek to mean military general. In the Hellenisti ...
'' - General and military governor of a
theme in the
Byzantine Empire
The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire primarily in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantin ...
.
*''
Stratelates
''Stratēlatēs'' ( el, στρατηλάτης, "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 ...
'' – A Greek translation for the rank of ''magister militum'' that was used in the late Roman and Byzantine armies.
*''
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.
*''
Tablifer'' – A standard-bearer for the guard cavalry.
*''
Tesserarius'' – Guard commander, one per ''centuria''.
*''
Tirones
Tirones ( la, tiro, tironis) were new recruits in the armies of the Roman Empire. A ''tiro'' could take up to six months before becoming a full ''miles'' (infantryman/private).
In the 4th century, Vegetius describes his ideal, rigorous training, ...
'' – 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'' (singular: ''Triarius'') 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 afford high qua ...
'' – Spearmen of the pre-Marian armies, equipped with the Hasta, who formed the third line of battle behind the ''Principes''.
*''
Tribuni angusticlavii A ''tribunus angusticlavius'' ("narrow-striped tribune"; plural: ''tribuni angusticlavii'') was a senior military officer in the Roman legions during the late Roman Republic and the Principate.
The ''tribunus angusticlavius'' was a junior military ...
'' – Military tribune of equestrian rank, five of whom were assigned to each legion.
*''
Tribunus militum'' - 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 (; c. 218 – 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 empi ...
as part of a policy of excluding senators from military commands.
*''
Tubicen'' – A trumpeter.
*''
Urbanae
The ''cohortes urbanae'' (Latin meaning ''urban cohorts'') of ancient Rome were created by Augustus to counterbalance the enormous power of the Praetorian Guard in the city of Rome and serve as a police service. They were led by the urban prefect ...
'' – A special police force of Rome, created to counterbalance the Praetorians.
*''
Velites'' – A class of light infantry in the army of the Roman Republic.
*''
Venator'' – A hunter (a type of ''
immunes'').
*''
Vexillarius'' – Bearer of a ''
vexillum'' (standard).
*''
Vigiles'' – were the firefighters and police.
Sub-units of the Roman legion
Before the
Marian reforms
The Marian reforms were reforms of the ancient Roman army implemented in 107 BC by the statesman Gaius Marius, for whom they were later named. The reforms originated as a reaction to the military and logistical stagnation of the Roman Republic in ...
of 107 BC the structure of the legions was as follows:
*''
Contubernium
A ''contubernium'' was a quasi-marital relationship in ancient Rome between a free citizen and a slave or between two slaves. A slave involved in such relationship was called ''contubernalis''.
The term describes a wide range of situations, from ...
'' – The smallest organized unit of soldiers in the Roman Army. It was composed of eight legionaries led by a ''
decanus''. When on the march a Legion would often march ''contubernium''-abreast (8-abreast). 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 unit of cavalry in the pre-Marian army, which usually consisted of 32 horsemen.
After the reforms of Gaius Marius, the organisation of the legions became standardised as follows:
*''
Contubernium
A ''contubernium'' was a quasi-marital relationship in ancient Rome between a free citizen and a slave or between two slaves. A slave involved in such relationship was called ''contubernalis''.
The term describes a wide range of situations, from ...
'' – The smallest organized unit of soldiers in the Roman Army. It was composed of eight legionaries led by a ''
decanus''. Ten ''contubernia'' formed a ''centuria''.
*''
Centuria
''Centuria'' (, plural ''centuriae'') is a Latin term (from the stem ''centum'' meaning one hundred) denoting military units originally consisting of 100 men. The size of the century changed over time, and from the first century BC through most ...
'' – 80 men under the command of a ''
centurion
A centurion (; la, centurio , . la, centuriones, label=none; grc-gre, κεντυρίων, kentyríōn, or ) was a position in the Roman army during classical antiquity, nominally the commander of a century (), a military unit of around 80 le ...
'' and his ''
optio
An , plural ( lat, italic=yes, optiō, , from , "to choose", so-called because an was chosen by a centurion), was a position in a '' centuria'' (century) of a Roman army similar to that of an executive officer. The main function of an was as ...
''. Six ''centuriae'' formed a ''cohors''.
*
''Cohors'' (cohort) – A ''cohors'' consisted of 480 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'', 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
A ''legatus'' (; anglicised as legate) was a high-ranking Roman military officer in the Roman Army, equivalent to a modern high-ranking general officer. Initially used to delegate power, the term became formalised under Augustus as the office ...
'', assisted by the ''
praefectus castrorum'' and other senior officers.
*''
Vexillatio
A ''vexillatio'' (plural ''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'' (plural ...
'' – 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