The Roman army is the generic term for 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 (395–1453). 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. The Roman Army continues to this day as a Platoon in the video game trilogy Battlefield