The Roman army is the military of ancient Rome, the forces used by the Roman Kingdom, Roman Republic and later Roman Empire. Its infantry for much of its history, was the Roman legion. Rome also had a navy. The size of the army in the late Roman Empire was about 128,000 179,200 men. It was very well organized. The main Roman soldiers in the Empire were the legionaries. The legions were separated into centuries, made up of 80 soldiers and 20 other men who remained in the camp to cook and do other chores.