Polybius first described the maniple in the mid-
2nd century BC. The manipular legion was organized into four lines, starting at the front: the
velites; the
hastati; the
principes; and the
triarii. These were divided by experience, with the younger soldiers at the front lines and the older soldiers near the back. One theory proposed by J. E. Lendon asserts that this order was adapted to the Roman culture of bravery, allowing an initial show of individual heroics among the younger soldiers. At the front of the legion organized into maniples, the
velites formed a swarm of soldiers which engaged the enemy at the start of the battle. Their duties involved skirmishing, and they often worked closely with the cavalry. Next, the
hastati were the youngest and least experienced soldiers, and therefore fought on the front-lines. They formed the first line of heavy infantry. The
principes were more experienced soldiers who stood behind the
hastati in battle. Finally, the
triarii were the veteran soldiers with the most experience. The second and third echelon generally formed with a one maniple space between each maniple and its neighbours. Retreating troops of the
velites could withdraw without disrupting those behind them. Where resistance was strong the
hastati would dissolve back through the Roman line, allowing the more experienced soldiers in the
principes to fight. In turn, the
principes could then yield to the hardened
triarii, if necessary. At this point in battle, the maniple greatly resembled the phalanx. According to Polybius, the most complete and likely the most accurate account, the legion consisted of 10 maniples of 120
hastati, 10 maniples of 120
principes, and 10 half strength maniples of
triarii containing 60 men each. With 1,200
velites and 300 cavalrymen a legion numbered 4,500 men. However, in times of great need the number might be reinforced up to 5,000. ==Equipment==