List of Roman Army Unit Types
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List of Roman Army Unit Types
This is a list of Roman army units and bureaucrats.
- Actuarius - A military who served food
- Adiutor - A camp or headquarters adjutant or assistant
- Aeneator - Military musician such as a bugler.
- Agrimensor - A surveyor (a type of immunes).
- Aquilifer - Bearer of the legionary eagle.
- Alaris - A cavalryman serving in an ala.
- Architecti - An engineer or artillery constructor.
- Armicustos - A soldier tasked with the administration and supply of weapons and equipment. A quartermaster.
- Ballistarius - An artillery operator (a type of immunes).
- Beneficiarius - A soldier performing an extraordinary task such as military policing or a special assignment.
- Bucinator - A trumpeter or bugler.
- Cacula - Servant or slave of a soldier.
- Capsarior - A medical orderly.
- Causarius - A soldier discharged for wounds or other medical reasons.
- Centurion - Officer rank, generally one per 80 soldiers, in charge of a centuria.
- Clinicus - A medic.
- Cornicen - A bugler.
- Doctor - A trainer, subdivisions for everything from weapons to horn blowing.
- Draconarius - Bearer of a cavalry standard.
- Decurion - Leader of a troop of cavalry (14-30 men). Often confused with decanus.
- Decanus - Leader of a contubernium (a legionary tent group of 8 men).
- Discens - Miles in training for an immunis position.
- 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.
- Duumviri navales - Two men elected to equip and repair the Roman navy.
- Equites singulares Augusti - Elite cavalry unit tasked to guard the Roman Emperors. Usually commanded by a tribunus of praetorian rank.
- 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.
- Evocatus Augusti - Praetorian Guard who had served out his time and obtained his discharge (missio), but had voluntarily enlisted again.
- Frumentarii - Officials of the Roman Empire during the 2nd and 3rd era. Often used as a Secret Service, mostly operating in uniform.
- 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.
- Hastatus Prior - A centurion commanding a manipulus or centuria of hastati. A high-ranking officer within a manipulus or centuria.
- Hastatus Posterior - A deputy to the hastatus prior
- Hastiliarius - A weapons instructor.
- Imaginifer - A standard-bearer carrying the imago - the standard which bore a likeness of the emperor, and, at later dates, his family.
- Immunes - Soldiers who were "immune" from combat duty and fatigues through having a more specialist role within the army.
- Katepano - A Byzantine military rank or military official.
- Legatus legionis - A legion commander of senatorial rank; literally the "deputy" of the emperor, who was the titular commander-in-chief.
- Legatus pro praetore - Provincial governor of senatorial rank with multiple legions under his command.
- Legionary - 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.
- Magister militum - High ranked commander in the late Roman Empire. Equivalent of a general.
- 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.
- Megas doux - Commander-in-chief of the Byzantine navy.
- Miles or Miles Gregarius - The basic private level foot soldier.
- Numerus - A unit of barbarian allies not integrated into the regular army structure. Later, a unit of border forces.
- Optio - One per century as second-in-command to the centurion. Could also fill several other specialized roles on an ad hoc basis.
- Pedites - The infantry of the early army of the Roman kingdom. The majority of the army in this period.
- Peditatus - A term referring to any infantryman in the Roman Empire.
- Pilus Prior - Senior centurion of a cohort.
- Pilus Posterior - Deputy to the pilus prior.
- Praefectus Castrorum - Camp prefect, third-in-command of the legion, also responsible for maintaining the camp, equipment, and supplies. Usually a former primus pilus.
- Praefectus Cohortis - Commander of a cohort.
- 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")
- Praetorians - A special force of bodyguards used by Roman Emperors.
- Primus Ordinis - 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.
- Princeps - 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).
- Princeps Prior - A centurion commanding a century of principes.
- Princeps Posterior - A deputy to the princeps prior.
- Principales - A group of ranks, including aquilifer, signifer, optio, and tesserarius. Similar to modern NCOs (Non-commissioned officers).
- Protectores Augusti Nostri (a.k.a. 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 Palatinae - An elite troop of soldiers created by the Emperor Constantine the Great to provide personal protection of the Emperor and his immediate family.
- Scorpionarius - An artilleryman operating a scorpio artillery piece.
- Signifer - Standard bearer of the Roman Legion.
- Socii - Troops from allied states in the pre-Marian army before the Social War (91-88 BC)
- 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.
- Strategos - General and military governor of a theme in the Byzantine Empire.
- Stratelates - 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 - A basic trainee.
- Triarii - 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.
- 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 as part of a policy of excluding senators from military commands.
- Tubicen - A trumpeter.
- Urbanae - 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).
Sub-units of the Roman legion
Before the Marian reforms of 107 BC the structure of the legions was as follows:
- Contubernium - 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 - 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 - 80 men under the command of a centurion and his optio. 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, assisted by the praefectus castrorum and other senior officers.
- Vexillatio - 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.