A cohort (from the Latin ''cohors'', plural ''cohortes'', see
wikt:cohors for full inflection table) was a standard tactical
military unit
Military organization or military organisation is the structuring of the armed forces of a state so as to offer such military capability as a national defense policy may require. In some countries paramilitary forces are included in a nation' ...
of a
Roman legion
The Roman legion ( la, legiō, ) was the largest military unit of the Roman army, composed of 5,200 infantry and 300 equites (cavalry) in the period of the Roman Republic (509 BC–27 BC) and of 5,600 infantry and 200 auxilia in the period of ...
. Although the standard size changed with time and situation, it was generally composed of 480 soldiers. A cohort is considered to be the equivalent of a modern military
battalion
A battalion is a military unit, typically consisting of 300 to 1,200 soldiers commanded by a lieutenant colonel, and subdivided into a number of companies (usually each commanded by a major or a captain). In some countries, battalions are ...
. The cohort replaced the ''
maniple'' following the
reforms
Reform ( lat, reformo) means the improvement or amendment of what is wrong, corrupt, unsatisfactory, etc. The use of the word in this way emerges in the late 18th century and is believed to originate from Christopher Wyvill's Association movement ...
attributed to
Gaius Marius
Gaius Marius (; – 13 January 86 BC) was a Roman general and statesman. Victor of the Cimbric and Jugurthine wars, he held the office of consul an unprecedented seven times during his career. He was also noted for his important refor ...
in 107 BC. Shortly after the military reforms of Marius, and until the middle of the third century AD, ten cohorts (about 5,000 men total) made up a legion. Cohorts were named "first cohort,” "second cohort," etc. The first cohort consisted of experienced
legionaries
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 Republi ...
, while the legionaries in the tenth cohort were less experienced.
Legionary cohort
A legionary cohort of the early empire consisted of six ''
centuriae
''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 ...
'', or centuries, each consisting of 80 legionaries, for a total of 480 legionaries. Prior to 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 ...
, each ''centuria'' consisted of 100 men, hence their name. Each ''centuria'' was commanded by 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 ...
, who increased in seniority from the sixth to the first centuries; thus, the centurion of the sixth century was the most junior in the cohort, while the centurion of the first century was the most senior. In order of increasing seniority, the six centurions were titled ''hastatus posterior'', ''hastatus prior'', ''princeps posterior'', ''princeps prior'', ''pilus posterior'', and ''pilus prior''. The ''pilus prior'' would command the cohort overall. The nomenclature of the ranks was derived from the Republican
''manipular'' legions, where troops were grouped into three rankings; ''
hastati
''Hastati'' (singular: ''hastatus'') were a class of infantry employed in the armies of the early Roman Republic, who originally fought as spearmen and later as swordsmen. These soldiers were the staple unit after Rome threw off Etruscan rule. ...
'' for the most inexperienced, followed by ''
principes
''Principes'' (Singular: ''princeps'') were spearmen, and later swordsmen, in the armies of the early Roman Republic. They were men in the prime of their lives who were fairly wealthy, and could afford decent equipment. They were the heavier in ...
'', and finally ''
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 ...
'' for the most experienced. ''Pilus'' was a rare alternative name for ''triarius'', reflecting their use as spearmen, ''pilus'' being the Latin word for spear.
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 ...
established by
Gaius Marius
Gaius Marius (; – 13 January 86 BC) was a Roman general and statesman. Victor of the Cimbric and Jugurthine wars, he held the office of consul an unprecedented seven times during his career. He was also noted for his important refor ...
in the 1st century BC formalised the command structure and composition of the legions. A century of 80 men was divided into ten ''
contubernia'', each of eight men, who shared a single A-frame
tent
A tent () is a shelter consisting of sheets of fabric or other material draped over, attached to a frame of poles or a supporting rope. While smaller tents may be free-standing or attached to the ground, large tents are usually anchored using gu ...
together. A contubernium was 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 officials in the Byzantine Empire, as well as for various positions in the Church, whence derives the English title "de ...
, appointed from within the contubernium, and was most likely the longest-serving legionary of the eight.
The decanus organised the erection of the unit's marching tent, and ensured his tent-mates kept things tidy.
A contubernium was assigned one to two pack
mules, which would carry heavier equipment and the contubernium's
mill
Mill may refer to:
Science and technology
*
* Mill (grinding)
* Milling (machining)
* Millwork
* Textile mill
* Steel mill, a factory for the manufacture of steel
* List of types of mill
* Mill, the arithmetic unit of the Analytical Engine early ...
, for grinding their daily grain ration into flour. These duties would be carried out by
camp slaves, of which one to two would be assigned to each contubernium. They tended to the pack mule, ensured legionaries had water on the march, and camp duties such as cooking, washing, and other specialised skills such as
smithing
A metalsmith or simply smith is a craftsperson fashioning useful items (for example, tools, kitchenware, tableware, jewelry, armor and weapons) out of various metals. Smithing is one of the oldest metalworking occupations. Shaping metal with a h ...
or
carpentry
Carpentry is a skilled trade and a craft in which the primary work performed is the cutting, shaping and installation of building materials during the construction of buildings, ships, timber bridges, concrete formwork, etc. Carpenters tr ...
. While encamped, younger legionaries may be sent out to fetch fodder, firewood, and water for the contubernium.
A century of 80 men would be commanded by 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 ...
, assisted by four junior officers. The pay of a centurion fluctuated depending on their seniority; the most junior centurion in a legion received around ten times the standard rate of pay, while the most senior legionary centurion could receive some forty times the standard rate of pay. The centurion was assisted by 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 ...
, who served as his second-in-command, and typically received double the legionary rate of pay. Third in seniority was a
tesserarius
A ''tesserarius'' ( lat, tesserārius, 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 ...
, who exercised command over the nightly guard duties, and were responsible for distributing the watchwords for the camp. A tesserarius was typically paid one-and-a-half times the standard rate of pay. A century also had a
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 59 in a legion. Within each cohort, the first century's ''signifer'' would b ...
, who carried the century's
standard Standard may refer to:
Symbols
* Colours, standards and guidons, kinds of military signs
* Standard (emblem), a type of a large symbol or emblem used for identification
Norms, conventions or requirements
* Standard (metrology), an object th ...
into battle, and also served as the unit's treasurer, keeping track of the pay and expenses of the men. Signifers typically received double pay. Lastly, a
cornicen
A ''cornicen'' (plural ''cornicines'') was a junior officer in the Roman army. The ''cornicens job was to signal salutes to officers and sound orders to the legions. The ''cornicines'' played the '' cornu'' (making him an ''aeneator''). ''Cornici ...
, equipped with a
cornu, served as a signaller, and received double pay. These officers would have their own support staff, tents, and mules. Thus, a cohort would consist of, on paper, 480 legionaries, 6 centurions, and 24 junior officers, with logistical support provided by 60-120 slaves, and 60-120 mules.
Ten cohorts of 480 legionaries would comprise a legion. Like the ranks of the centurions, cohorts would also follow a pattern of seniority; a legion's tenth cohort was its most junior, while the first cohort was the most prestigious, with its ranks filled with either veteran troops, or the best recruits. The commander of the first cohort's first century was known as the ''primus pilus'' or "first spear", a legion's most senior centurion. The ''primus pilus'' was eligible for promotion to ''
praefectus castrorum
The ''praefectus castrorum'' ("camp prefect") was, in the Roman army of the early Empire, the third most senior officer of the Roman legion after the legate (''legatus'') and the senior military tribune (''tribunus laticlavius''), both of whom w ...
'' or camp prefect, the third most senior officer in a legion, responsible for the day-to-day administration of a legion.
The first cohort was an aberration in that it consisted of five double-strength ''centuriae'', each of 160 men, for a total of 800 men, as opposed to six centuries of 80 men. It was the unique honour of the first cohort's
aquilifer
An ''aquilifer'' (, "eagle-bearer") was a soldier signifer bearing the eagle standard of a Roman legion. The name derives from the type of standard, '' aquila'' meaning "eagle" (which was the universal type used since 106 BC), and ''ferre'', the ...
to carry the legion's ''
aquila'', or eagle, standard into battle, which possessed a quasi-religious importance to the legionaries. Loss of an eagle was considered a mark of extreme shame and disgrace for a legion. A legion's first cohort also had an
imaginifer
The ''imaginifer'' was one of the ''signiferi'' in a legion in the times of the Roman Empire, who carried the ''imago'' (the image) of the emperor.
The ''imaginifer'' was added to the ranks of the legions when the Imperial cult was first establ ...
, who carried an ''imago'' of the reigning
Emperor
An emperor (from la, imperator, via fro, empereor) is a monarch, and usually the sovereignty, sovereign ruler of an empire or another type of imperial realm. Empress, the female equivalent, may indicate an emperor's wife (empress consort), ...
, typically a three-dimensional relief of their likeness made of beaten metal.
Each cohort also had a small artillery corps. According to Vegetius, each century was equipped with a ''
scorpio'', a small torsion-powered ballista, for a total of six per cohort. A contubernium would be deputed to operate the weapon, when required. Like most ancient artillery, these weapons were likely used in fixed positions for infantry defence, or in sieges. Each cohort also had one ''
onager
The onager (; ''Equus hemionus'' ), A new species called the kiang (''E. kiang''), a Tibetan relative, was previously considered to be a subspecies of the onager as ''E. hemionus kiang'', but recent molecular studies indicate it to be a distinct ...
'', a stone-throwing torsion-powered catapult. Vegetius stipulates that they were transported fully-assembled on ox-drawn carts, to ensure the onager was ready for immediate use. Additional equipment, such as
rams
In engineering, RAMS (reliability, availability, maintainability and safety)towers
A tower is a tall structure, taller than it is wide, often by a significant factor. Towers are distinguished from masts by their lack of guy-wires and are therefore, along with tall buildings, self-supporting structures.
Towers are specific ...
, or larger
ballistae
The ballista (Latin, from Greek βαλλίστρα ''ballistra'' and that from βάλλω ''ballō'', "throw"), plural ballistae, sometimes called bolt thrower, was an ancient missile weapon that launched either bolts or stones at a distant ta ...
were added as needed. Thus, by extrapolation, a legion had an artillery train of some sixty ''scorpios'' and ten ''onagers''.
Types of cohort
![Romeinse_munten_denarius_Marcus_Antonius_Chortis_Speculatorum](https://upload.wikimedia.org/wikipedia/commons/b/bd/Romeinse_munten_denarius_Marcus_Antonius_Chortis_Speculatorum.jpg)
*''Cohors alaria'': allied or auxiliary unit
*''Cohors quinquagenaria'': auxiliary, nominally 500 strong
*''Cohors milliaria'': auxiliary, nominally 1000 strong
*''Cohors classica'': auxiliary unit originally formed of sailors and marines
*''Cohors equitata'' (LA): unit of auxiliary infantry with attached mounted squadrons
*''Cohors peditata'' (LA): infantry unit
*''Cohors sagittaria'': infantry auxiliary unit of bowmen
*''Cohors speculatorum'' (LA): guard unit of
Mark Antony
Marcus Antonius (14 January 1 August 30 BC), commonly known in English as Mark Antony, was a Roman politician and general who played a critical role in the transformation of the Roman Republic from a constitutional republic into the autoc ...
composed of scouts
*''Cohors torquata'' (LA): auxiliary unit granted a ''torques'' (military decoration)
*''Cohors tumultuaria'' (from ''tumultus'', "chaos"):
irregular auxiliary unit
Other Roman cohorts
Although not part of a legion, some paramilitary corps in Rome consisted of one or more cohorts:
*The nine ''cohortes praetoriae'', never grouped to a legion, the infamous
Praetorians
The Praetorian Guard (Latin language, Latin: ''cohortēs praetōriae'') was a unit of the Imperial Roman army that served as personal Bodyguard, bodyguards and military intelligence, intelligence agents for the Roman emperors. During the Roman R ...
. The term was first used to refer to the bodyguard of a general during the
Republic
A republic () is a "state in which power rests with the people or their representatives; specifically a state without a monarchy" and also a "government, or system of government, of such a state." Previously, especially in the 17th and 18th c ...
; later, a unit of imperial guards (temporarily restyled ''cohors palatina'' (imperial cohort),
["Hence adj. Pălātīnus -a -um ''Palatine''; Apollo, ''whose temple was on the Palatine'', Hor.; also ''relating to the imperial palace, imperial'': Ov."—] c. 300 AD, under
Diocletian
Diocletian (; la, Gaius Aurelius Valerius Diocletianus, grc, Διοκλητιανός, Diokletianós; c. 242/245 – 311/312), nicknamed ''Iovius'', was Roman emperor from 284 until his abdication in 305. He was born Gaius Valerius Diocles ...
's
tetrarchy
The Tetrarchy was the system instituted by Roman emperor Diocletian in 293 AD to govern the ancient Roman Empire by dividing it between two emperors, the '' augusti'', and their juniors colleagues and designated successors, the '' caesares' ...
).
**''Cohors togata'' was a unit of the Praetorian Guard in civilian clothes tasked with duties within the ''
pomerium
The ''pomerium'' or ''pomoerium'' was a religious boundary around the city of Rome and cities controlled by Rome. In legal terms, Rome existed only within its ''pomerium''; everything beyond it was simply territory (''ager'') belonging to Rome.
...
'' (sacred center of the capital, where all armed forces were forbidden).
*''
Cohortes 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 ...
'', "urban cohort": Law enforcement officers patrolling in the capital.
*''
Cohortes vigilum
The ''Vigiles'' or more properly the ''Vigiles Urbani'' ("watchmen of the City") or ''Cohortes Vigilum'' ("cohorts of the watchmen") were the firefighters and police of ancient Rome.
History
The ''Triumviri Nocturni'' (meaning ''three men of th ...
'', "watchmen": Law enforcement officers forming the fire brigade in the capital.
*''Cohors Germanorum'' (LA): the unit of ''
Germani custodes corporis'' (imperial body guards recruited in
Germania
Germania ( ; ), also called Magna Germania (English: ''Great Germania''), Germania Libera (English: ''Free Germania''), or Germanic Barbaricum to distinguish it from the Roman province of the same name, was a large historical region in north- ...
).
Furthermore, the Latin word ''cohors'' was used in a looser way to describe a rather large "company" of people (see, for instance, ''
cohors amicorum {{short description, Roman Latin term meaning "cohort of friends"
''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 Ro ...
'').
See also
*
Auxiliaries (Roman military)
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 inf ...
*
List of Roman auxiliary regiments
This article lists ', non-legionary auxiliary regiments of the imperial Roman army, attested in the epigraphic record, by Roman province of deployment during the reign of emperor Hadrian ( AD 117–138).
The index of regimental names expla ...
References
{{reflist
Infantry units and formations of ancient Rome
Military units and formations of the Roman Empire
Roman tactical formations
Military units and formations of the Roman Republic
Roman legions