Our notice of the Roman legion would be incomplete without some description of the camp in which the soldier virtually lived. A Roman army never halted for a single night without forming a regular intrenchment capable of holding all the fighting men, the beasts of burden, and the baggage. During the winter months, when the army could not retire into some city, it was compelled to live in the camp, which was arranged and fortified according to a uniform plan, so that every company and individual had a place assigned. We cannot tell when this practice of intrenchment began; it was matured gradually, like all other things pertaining to all arts. The system was probably brought to perfection during the wars with Hannibal. Skill in the choice of ground, giving facilities for attack and defence, and for procuring water and other necessities, was of great account with the generals. An area of about five thousand square feet was allowed for a company of infantry, and ten thousand feet for a troop of thirty dragoons. The form of a camp was an exact square, the length of each side being two thousand and seventeen feet; there was a space of two hundred feet between the ramparts and the tents to facilitate the marching in and out of soldiers, and to guard the cattle and booty; the principal street was one hundred feet wide, and was called Principia. The defences of the camp consisted of a ditch, the earth from which was thrown inward, and of strong palisades of wooden stakes driven into the top of the earthwork so formed; the ditch was sometimes fifteen feet deep, and the _vallum_, or rampart, ten feet in height. When the army encamped for the first time the tribunes administered an oath to each individual, including slaves, to the effect that they would steal nothing out of the camp. Every morning at daybreak the centurions and the equites presented themselves before the tents of the tribunes, and the tribunes in like manner presented themselves before the praetorian, to learn the orders of the consuls, which through the centurions were communicated to the soldiers. Four companies took charge of the principal street, to see that it was properly cleaned and watered; one company took charge of the tent of the tribune; a strong guard attended to the horses, and another of fifty men stood beside the tent of the general, that he might be protected from open danger and secret treachery. The _velites_ mounted guard the whole night and day along the whole extent of the vallum, and each gate was guarded by ten men; the _equites_ were intrusted with the duty of acting as sentinels during the night, and most ingenious measures were adopted to secure their watchfulness and fidelity. The watchword for the night was given by the commander-in-chief. "On the first signal being given by the trumpet, the tents were all struck and the baggage packed; at the second signal, the baggage was placed upon the beasts of burden; and at the third, the whole army began to move.