Since curiously enough the Emperor usually intrusts to the Prætorian Præfect the task of hearing legal “appeals to Cæsar” from the imperial half of the provinces, it is not unusual to name two præfects, nominally of equal authority but with one of them often a trained jurist, and the other more concerned with the military management of the corps. This has the additional advantage of making it harder to start an insurrection,--each Præfect will keep watch upon his colleague. Inasmuch as the Emperor is now absent from Rome a detachment of the guard is away with him, but the world being in general peace there is no need (as in a major war) for the entire corps to go forth to reinforce the frontier legions. The Prætorians are therefore on duty as usual; one cohort at the Palatine, the remainder barracked at their great camp. The _Castra Prætoria_[163] is more than a mere cantonment; it is a real fortress, only to be stormed after desperate fighting. We enter it from the central gateway (_Porta Prætoria_) which looks straight westward upon the city. A lofty wall of masonry, brick, and concrete, crowned by suitable battlements, surrounds a vast rectangular area about 1400 feet wide, and 1100 feet deep. The greater and lesser gates are crowned with fine marble sculptures almost worthy of the Palatine. In the center of the area rises a mass of office buildings, a residence for the Præfect and a small temple to the military gods such as Mars, and especially to the deified emperors. The side walls of the inclosure are extended on the inside by an enormous system of arches and vaulting, making many deep chambers where thousands of men are easily barracked. In the open area fountains are playing, and the sun is sending a flying glory from the burnished armor of a cohort standing at rest, while certain officers affix medals of honor, or bestow spears and banners of honor upon various men who have lately distinguished themselves during some detached duty in Mauretania. Everything about the place betrays a perfect “police”; all commands are executed with extreme promptness; and every individual seems absolutely to know his part, as being one cog in an enormous war machine, into the making of which has entered an almost inconceivable amount of skill and energy. =266. Organization and Discipline of the Prætorians.=--The Prætorians are organized much as the ordinary legionary troops with certain proud modifications. The regular legions can be recruited from all over the Empire; the Prætorians are still drawn only from Italy. They receive twice the pay of the legionaries, and their term of service is only sixteen years as against twenty with the regulars. Besides these advantages, and the joy of living near to the pleasures of Rome, their discipline is said to be much easier.