What were the different types of Roman army units?

The Roman army featured a diverse array of units, ranks, and specialized roles spanning from the early Republic to the late empire. These ranged from the smallest tactical sub-subunits like the eight-man contubernium to specialized auxiliary forces, cavalry, engineers, and command staff. Units evolved significantly over time, transitioning from early republican groups like maniples to the field armies of the late empire.

What we know

• The contubernium was the smallest organized sub-subunit in the Roman Army, composed of eight legionaries who shared a tent, equipment, and a mule. [4]
• Auxilia were non-citizen troops introduced as forces attached to citizen legions by Augustus following his reorganization of the Imperial Roman army starting in 30 BC. [2]
• Ballistarii served as infantrymen and artillery operators who handled ballistae and were classed as immunes, meaning they were exempt from fatigue duties like entrenching. [5]
• The maniple was a tactical unit of the Roman Republican armies adopted during the Samnite Wars before being replaced by cohorts as organizational units. [3]

Where to go next

• the bigger pictureHow did the Roman legion function in battle?
• a case in pointWhat role did auxiliary troops play in the Roman military?
• how it workedHow did the contubernium maintain discipline and morale?
• whoWhat were the duties of a Roman centurion?
• whenHow did Roman military units change from the Republic to the Empire?
• an unexpected connectionHow did Roman military titles evolve into medieval nobility?Specific late Roman military command titles such as comes and dux directly evolved into the medieval titles of count and duke.

Sources

• [1]list of Roman army unit types (Wikidata Q3113114) · CC0 1.0
• [2]List of Roman army unit types · CC BY-SA 4.0
• [3]Maniple (military unit) · CC BY-SA 4.0
• [4]Contubernium (Roman army unit) · CC BY-SA 4.0
• [5]Ballistarius · CC BY-SA 4.0

Your path

1. What is the Helladic chronology system?
2. /What is beta decay in nuclear physics?
3. /Who was Florian Cajori and what did he write about?
4. /What were the different types of Roman army units?