The Roman army (Latin: exercitus Romanus, literally: Roman Army; Ancient Greek: στρατός Ῥωμαίων, transcription: stratos Romaion) is a term encompassing the terrestrial armed forces deployed by the Roman Kingdom (to c. 500 BC), the Roman Republic (500–31 BC), the Roman Empire (31 BC – 395/476 AD) and its successor the East Roman or Byzantine Empire. It is thus a term that spans approximately 2,000 years, during which the Roman armed forces underwent numerous permutations in composition, organization, equipment and tactics, while conserving a core of lasting traditions.

Historical phases

The development of the Roman army was divided into eight phases.

Early Roman army (c. 500 B.C. to c. 300 B.C.)

The Early Roman army of the Roman kingdom and of the early republic (to c. 300 BC). During this period, when warfare chiefly consisted of small-scale plundering-raids, it has been suggested that the Roman army followed Etruscan or Greek models of organisation and equipment. The early Roman army was based on an annual levy.