The Early Roman Army Battle Tactics

Another part of the army's tactics was to build a camp at the end of every day's march. The afternoon saw the rapid construction of an army camp, and the night was reserved for rest from the day's march and labor. The camp served multiple purposes. First and foremost it served as a nightly defense against surprise attacks and as a base to retreat to just in case a defeat should ever happy. The construction of camps also gave the soldiers and officers a place to rest peacefully. Much of the Roman army's success depended on coolness of temper.
A Roman soldier was kept from nervous strain as long as possible, so as to perform well under the intense stress of battle. The existence of a camp contributed greatly to this. It also exemplified the tenacity of the Romans. If defeated in battle, they would not have to retreat far, and they would fight again the next day, if not the same day. Also, instead of being pushed back far back into their own lands, the camp served as a fortified stronghold, which could be used to fend off the left over attackers from the previous battle until reinforcements could arrive.

The way the battles were fought showed why the army became so powerful. The main force advanced in three lines, consisting of the Hastati, Principes, and Triarii, in that order. The Velites formed a light screen in front. Though it is unclear the exact formation the army took, it is generally agreed that the maniples (units of 120 men) were arranged in a checkerboard formation, so the first line could fall back if need through the lines of the second without breaking up formation. As the enemy approached, the Velites would pepper the enemy with javelin fire until the depleted their ammunition or else the charging enemy got too close, and then they would retreat through the lines of the Hastati and on to the back of the army. When the enemy came within thirty or so yards, the Hastati would release a volley of their pila, to further weaken the lines and the morale of the enemy. When the fighting became hot, and the first line Hastati become tired or incur too many losses, they would fall back through the Principes, in which case they would pick up the fight with renewed strength. If they continued to fight and lose ground, then the Principes would fall back through the line of Triarii, which were the last line of defense. They then would present the enemy with a line of heavy spears and fresh strength, which would hopefully be enough to win the battle. As the Roman saying went, "It has come to the Triarii", meant that the battle had progressed to the bitter end, and was possible the turning point.