=278. The Auxiliary Cohorts: the Second Grand Division of the Army.=--But it is absolutely necessary to have a mobile force, composed of troops of many kinds, especially cavalry, archers, slingers, and light spearmen for scouting. These men are often enlisted in the un-Romanized provinces, and are allowed to keep their native arms and discipline. As a rule they are organized in unattached cohorts, either in “large” cohorts of 1000 men with ten centuries, or “small” cohorts of 480 with six so-called centuries. Their commander is regularly a “Præfect,” commonly an officer who, like Quadratus, has graduated from the stern school of the centurion in a legion. Auxiliary cohorts are often embodied and disbanded, they have no such glorious history and traditions as the legions, but they have a distinctive name and a number. Quadratus was assigned to the command of a new “large” cohort made up of tall blonde Germans who were glad to forget their feuds with the Romans, cross the Rhine, and take the Emperor’s pay, swearing to him the great oath of implicit military allegiance (_the sacramentum_). The government is far too wise, however, to leave such aliens too near their homes. Quadratus was, therefore, promptly ordered to march his “Sixth Nervan” (so named in honor of the then Emperor Nerva)[171] to the Danube. The day the new Præfect quitted his old comrades of the Second Augustan he drew from the legionary chest all the savings from his pay, plus the sums deposited there after each bonus or donation wherewith the Emperors were always conciliating the army. He had also long since joined a self-help organization among the officers whereby he was to receive a fixed sum for his outfit whenever he received promotion.[172] He thus started upon his career as an upper officer a tolerably rich man. =279. The Præfect of the Camps and the Legate of the Legion.=--As Præfect of the Sixth Nervan he won the good opinion of Trajan in both of the desperate Dacian Wars and then in the campaign against Parthia. As the next step, he was appointed by imperial patent “Præfect of the Camps”--the second in command of a legion, not responsible, indeed, for its conduct in battle, but with almost complete authority over its management and discipline while in its great permanent garrisons, subject only (in extreme cases) to the final authority of the commanding legate.