The Roman army (Latin: exercitus Romanus) was the terrestrial armed forces deployed by the Romans throughout the duration of Ancient Rome, from the Roman Kingdom (to c. 500 BC) to the Roman Republic (500–31 BC) and the Roman Empire (31 BC – 395), and its medieval continuation the Eastern Roman Empire. It is thus a term that may span approximately 2,206 years (753 BC to 1453 AD), during which the Roman armed forces underwent numerous permutations in composition, organisation, equipment and tactics, while conserving a core of lasting traditions.