A cohort (from the Latincohors, pl.: cohortes; see wikt:cohors for full inflection table) was a standard tactical military unit of a Roman legion. Although the standard size changed with time and situation, it was generally composed of 480 soldiers.[1] A cohort is considered to be the equivalent of a modern military battalion. The cohort replaced the maniple.[2] From the late second century BC 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, while the legionaries in the tenth cohort were less experienced.
A legionary cohort of the early empire consisted of six centuriae, or centuries, each consisting of 80 legionaries, for a total of 480 legionaries. Early in the Republic, each centuria consisted of 100 men, hence their name. Each centuria was commanded by a centurion, 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.[citation needed] The nomenclature of the ranks was derived from the Republican manipular legions, where troops were grouped into three rankings; hastati for the most inexperienced, followed by principes, and finally triarii for the most experienced. Pilus was a name for a maniple of triarii, reflecting their use as spearmen, pilum being the Latin word for a javelin.[3][4]
A century of 80 men was divided into ten contubernia, each of eight men, who shared a single A-frame tent together. A contubernium was led by a decanus, appointed from within the contubernium, and was most likely the longest-serving legionary of the eight.[5] The decanus organised the erection of the unit's marching tent, and ensured his tent-mates kept things tidy.[6] A contubernium was assigned one to two pack mules, which would carry heavier equipment and the contubernium's mill, 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 or carpentry. 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, 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.[7] The centurion was assisted by an optio, who served as his second-in-command, and typically received double the legionary rate of pay. Third in seniority was a tesserarius, 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, who carried the century's standard 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, equipped with a cornu, served as a signaller, and received double pay.[8] 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.[9] 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 primipilus,[4] a legion's most senior centurion. The primus pilus was eligible for promotion to praefectus castrorum 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 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, who carried an imago of the reigning Emperor, typically a three-dimensional relief of their likeness made of beaten metal.[10]
Each cohort also had a small artillery corps. According to Vegetius, a 4th-century Roman author, 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.[11] Like most ancient artillery, these weapons were likely used in fixed positions for infantry defence, or in sieges.[12] Each cohort also had one onager, 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.[13] Additional equipment, such as rams, towers, or larger ballistae were added as needed. Thus, by extrapolation, a legion had an artillery train of some sixty scorpios and ten onagers.
Cohors torquata (LA)[clarification needed]: 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 Praetorians. The term was first used to refer to the bodyguard of a general during the Republic; later, a unit of imperial guards (temporarily restyled cohors palatina (imperial cohort),[14] c. 300 AD, under Diocletian's tetrarchy).
Cohors togata was a unit of the Praetorian Guard in civilian clothes tasked with duties within the pomerium (sacred center of the capital, where all armed forces were forbidden).
Cohortes urbanae, "urban cohort": Law enforcement officers patrolling in the capital.
Cohortes vigilum, "watchmen": Law enforcement officers forming the fire brigade in the capital.
The Roman legion, the largest military unit of the Roman army, was composed of Roman citizens serving as legionaries. During the Roman Republic the manipular legion comprised 4,200 infantry and 300 cavalry. After the Marian reforms in 107 BC the legions were formed of 5,200 men and were restructured around 10 cohorts, the first cohort being double strength. This structure persisted throughout the Principate and middle Empire, before further changes in the fourth century resulted in new formations of around 1,000 men.
The Praetorian Guard was an elite unit of the Imperial Roman army that served as personal bodyguards and intelligence agents for the Roman emperors.
The Roman legionary was a citizen soldier of the Roman army. These soldiers would conquer and defend the territories of ancient Rome during the late Republic and Principate eras, alongside auxiliary and cavalry detachments. At its height, Roman legionaries were viewed as the foremost fighting force in the Roman world, with commentators such as Vegetius praising their fighting effectiveness centuries after the classical Roman legionary disappeared.
The Roman army was the armed forces deployed by the Romans throughout the duration of Ancient Rome, from the Roman Kingdom to the Roman Republic and the Roman Empire, and its medieval continuation, the Eastern Roman Empire. It is thus a term that may span approximately 2,206 years, during which the Roman armed forces underwent numerous permutations in size, composition, organisation, equipment and tactics, while conserving a core of lasting traditions.
In the Roman army during classical antiquity, a centurion, was a commander, nominally of a century, a military unit originally consisting of 100 legionaries. The size of the century changed over time, and from the first century BC through most of the imperial era was reduced to 80 men.
Centuria is a Latin term 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 the imperial era the standard size of a centuria was 100 men. By the time of Roman Empire, ordo became a synonym of centuria.
The contubernium was the smallest organized unit of soldiers in the Roman Army and was composed of ten legionaries, essentially the equivalent of a modern squad, although unlike modern squads contubernia seemed to serve no tactical role in battle. It was likely used to maintain morale and group solidarity by keeping soldiers in close contact with each other. The men within the contubernium were known as contubernales. Ten contubernia, each led by a decanus, were grouped into a centuria of 100 men, which was commanded by a centurion. Soldiers of a contubernium shared a tent, and could be rewarded or punished together as a unit.
An optio, was a position in a centuria (century) of a Roman army similar to that of an executive officer. The main function of an optio was as an optio centuriae, the second-in-command of a century, although there were many other roles an optio could adopt.
The primus pilus 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 legate. The primus pilus would remain in command for one year. They could continue to serve in the army after their term ended if there was a vacancy in command or if they wished to become an independent commander of an auxilia unit or the praefectus castrorum.
The auxilia were introduced as non-citizen troops attached to the citizen legions by Augustus after his reorganisation of the Imperial Roman army from 27 BC. By the 2nd century, the Auxilia contained the same number of infantry as the legions and, in addition, provided almost all of the Roman army's cavalry and more specialised troops. The auxilia thus represented three-fifths of Rome's regular land forces at that time. Like their legionary counterparts, auxiliary recruits were mostly volunteers, not conscripts.
A turma, 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 translated as "squadron" but so is the term ala, a unit that was made up of several turmae.
This article concerns the Roman auxiliary regiments of the Principate period originally recruited in the western Alpine regions of the empire. The cohortes Alpinorum came from Tres Alpes, the three small Roman provinces of the western Alps, Alpes Maritimae, Alpes Cottiae and Alpes Graiae. The cohortes Ligurum were originally raised from the Ligures people of Alpes Maritimae and Liguria regio of NW Italia.
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 "dean". It is unrelated to the position of deacon.
The Imperial Roman Army was the military land force of the Roman Empire from 27 BC to 476 AD, and the final incarnation in the long history of the Roman army. This period is sometimes split into the Principate and the Dominate (284–476) periods.
Roman infantry tactics are the theoretical and historical deployment, formation, and manoeuvres of the Roman infantry from the start of the Roman Republic to the fall of the Western Roman Empire. The focus below is primarily on Roman tactics: the "how" of their approach to battle, and how it stacked up against a variety of opponents over time. It does not attempt detailed coverage of things like army structure or equipment. Various battles are summarized to illustrate Roman methods with links to detailed articles on individual encounters.
Princeps prior was a high-ranking Roman centurion and a member of the legion. Each of the ten cohorts that made up a legion had at its head the rank of pilus prior followed by the princeps prior. There is some controversy as to the precise order of the ranks below the pilus prior but this rank was followed by princeps prior if the order is based on seniority.
Traianus Mucianus was a Roman soldier of Thracian origins of the second half of the Third Century AD who rose from the lowest ranks of the army to senior commands. He was almost certainly a remarkable soldier. However, the successive promotions he secured in the latter part of his career are thought to owe much also to the favour shown him by men highly placed in the Imperial entourage whose patronage secured him advantageous postings in the Imperial comitatus, the mobile field force under the direct command of the Emperor, that was undergoing massive expansion at this time.
By the size of the Roman army is meant the changes in the number of its contingents: legions, auxiliaries, Praetorian cohorts, Urban cohorts, vigiles, and naval forces over the course of twelve centuries – from 753 BC to AD 476.
↑ "Hence adj. Pălātīnus -a -um Palatine; Apollo, whose temple was on the Palatine, Hor.; also relating to the imperial palace, imperial: Ov."—Simpson, D. P. (1968). Cassell's Latin Dictionary (5thed.). New York: Macmillan General Reference. p.420. ISBN0-02-522570-7.
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