The Praetorian cohort was a select body of troops instituted by Augustus to protect his person, and consisted of ten cohorts, each of one thousand men, chosen from Italy. This number was increased by Vitellius to sixteen thousand, and they were assembled by Tiberius in a permanent camp, which was strongly fortified. They had peculiar privileges, and when they had served sixteen years, received twenty thousand sesterces, or more than one hundred pounds sterling. Each Praetorian had the rank of a centurion in the regular army. Like the body-guard of Louis XIV., they were all gentlemen, and formed gradually a great power, like the janissaries at Constantinople, and frequently disposed of the purple itself. It would thus appear that the centurion only received twice the pay of the ordinary legionary. There was not therefore so much difference in rank between a private and a captain as in our day. There were no aristocratic distinctions in the ancient world so marked as in the modern. [Sidenote: The Roman camp.] [Sidenote: The guardianship of the camp.] [Sidenote: The breaking up of the camp.] Our notice of the Roman legion would be incomplete without allusion to 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. When the army could not retire, during the winter months, into some city, it was compelled to live in the camp. It 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 the art of war. The system was probably brought to perfection during the wars with Hannibal. Skill in the choice of ground, giving facilities for attack and defense, 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 between the ramparts and the tents of two hundred feet 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 defenses of the camp consisted of a ditch, the earth from which was thrown inwards, and strong palisades of wooden stakes upon 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