=Military Exercises.=--Rome had no gymnasium; the future soldiers exercised themselves on the parade-ground, the Campus Martius, on the other side of the Tiber. There the young man marched, ran, leaped under the weight of his arms, fenced with his sword, hurled the javelin, wielded the mattock, and then, covered with dust and with perspiration, swam across the Tiber. Often the older men, sometimes even the generals, mingled with the young men, for the Roman never ceased to exercise. Even in the campaign the rule was not to allow the men to be unoccupied; once a day, at least, they were required to take exercise, and when there was neither enemy to fight nor intrenchment to erect, they were employed in building roads, bridges, and aqueducts. =The Camp.=--The Roman soldier carried a heavy burden--his arms, his utensils, rations for seventeen days, and a stake, in all sixty Roman pounds. The army moved more rapidly as it was not encumbered with baggage. Every time that a Roman army halted for camp, a surveyor traced a square enclosure, and along its lines the soldiers dug a deep ditch; the earth which was excavated, thrown inside, formed a bank which they fortified with stakes. The camp was thus defended by a ditch and a palisade. In this improvised fortress the soldiers erected their tents, and in the middle was set the Prætorium, the tent of the general. Sentinels mounted guard throughout the night, and so prevented the army from being surprised. =The Order of Battle.=--In the presence of the enemy the soldiers did not form in a solid mass, as did the Greeks. The legion was divided into small bodies of 120 men, called maniples because they had for standards bundles of hay.[123] The maniples were ranged in quincunx form in three lines, each separated from the neighboring maniple in such a way as to manœuvre separately. The soldiers of the maniples of the first line hurled their javelins, grasped their swords, and began the battle. If they were repulsed, they withdrew to the rear through the vacant spaces. The second line of the maniples then in turn marched to the combat. If it was repulsed, it fell back on the third line. The third line was composed of the best men of the legion and was equipped with lances. They received the others into their ranks and threw themselves on the enemy. The army was no longer a single mass incapable of manœuvring; the general could form his lines according to the nature of the ground. At Cynoscephalæ, where for the first time the two most renowned armies of antiquity met, the Roman legion and the Macedonian phalanx, the ground was bristling with hills; on this rugged ground the 16,000 Macedonion hoplites could not remain in order, their ranks were opened, and the Roman platoons threw themselves into the gaps and demolished the phalanx.