Imperial Roman army

Roman army
Exercitus Romanus
Vexillum with the imperial aquila
Active27 BC to 476 AD
CountryRoman Empire
TypeArmy
RoleLand warfare
Size450,000 (211 AD)
Part ofRoman military
Nickname(s)List of names
EquipmentList of equipment
DecorationsList of decorations
Commanders
Commander-in-chiefEmperor (de facto)
Consuls (de jure)

The Imperial Roman Army was the military land force of the Roman Empire from 27 BC to 476 AD,[1] and the final incarnation in the long history of the Roman army. This period is sometimes split into the Principate (27 BC – 284 AD) and the Dominate (284–476) periods.

Under Augustus (r. 27 BC – AD 14), the army consisted of legions, eventually auxilia and also numeri.[2] By the end of Augustus' reign, the imperial army numbered some 250,000 men, equally split between 25 legions and 250 units of auxiliaries. The numbers grew to a peak of about 450,000 by 211, in 33 legions and about 400 auxiliary units. By then, auxiliaries outnumbered legionaries substantially. From this peak, numbers probably underwent a steep decline by 270 due to plague and losses during multiple major invasions by the Germanic Tribal Folk. Numbers were restored to their early 2nd-century level of c. 400,000 (but probably not to their 211 peak) under Diocletian (r. 284–305).

After the Empire's borders became settled (on the Rhine-Danube line in Europe) by AD 68, virtually all military units (except the Praetorian Guard) were stationed on or near the borders, in roughly 17 of the 42 provinces of the empire in the reign of Hadrian (r. 117–138).

  1. ^ The Imperial Roman Army, Yann Le Bohec, Routledge, 28 Oct 2013
  2. ^ Goldsworthy, Adrian (2000). Roman Warfare