PRAETORIANS. In the early Roman republic, praetor (q.v.) meant commander of the army: in the later republic praetor and propraetor were the usual titles for provincial governors with military powers. Accordingly, the general's quarters in a camp came to be called praetorium, 6 and one of the gates porta praetoria, and the general's bodyguard cohors praetoria, or, if large enough to include several cohorts, cohortes praetoriae. Under the empire the nomenclature continued with some changes. In particular cohortes praetoriae now designated the imperial bodyguard. This, as founded by Augustus, consisted of nine cohorts, each 1000 strong, some part of which was always with the emperor, whether in Rome or elsewhere. In A.D. 23 his successor Tiberius concentrated this force on the eastern edge of Rome in fortified barracks: hence one cohort in turn, clad in civilian garb, was sent to the emperor's house on the Palatine, and large detachments could be despatched to foreign wars. The men were recruited voluntarily, in Italy or in Italianized districts, and enjoyed better pay and shorter service than the regular army: they were under praefecti praetorio (usually two; later, sometimes three, rarely only one), who during most of the empire might not be senators. This force was the only body of troops in Rome (save a few cohortes urbanae, a fire brigade, and some non-Roman personal guards of the emperor), or, indeed, anywhere near the capital. Accordingly it could make or unmake emperors in crises at the accession of Claudius in A.D. 41, in 68-69, and again late in the second century. But its normal influence was less than is often asserted. Moreover, its prefects, since they were two and liable to be disunited, and since they could not be senators, neither combined with the 6 In permanent forts and fortresses, praelorium probably denoted strictly a residence: the official headquarters building (though commonly styled praelorium by moderns) was the principta. On the other hand praetorium could denote any lord's residence, even on a civilian's estate.
senators to restore an oligarchy nor themselves aspired as pretenders to the throne. These prefects were at first soldiers, but later mostly lawyers who relieved the emperors of various civil and criminal jurisdiction. In the second century the praetorian cohorts became ten in number, and at the end of it Septimius Severus reorganized them so that they consisted practically of barbarian soldiers and held constant conflict with the people of Rome. At the end of the third century the praefecti praetorio were reconstituted as four officers, each ruling one quarter of the now divided empire. In 312 the Praetorian Guard was suppressed by Constantine. Their barracks at Rome covering a rectangle of 39 acres (1210 by 1410 ft.), were included by Aurelian in the walls of Rome, and three sides of the enceinte can still be seen near the Porta Pia, with brickwork as old as Tiberius: the interior (now barracks for the Italian army) is archaeologically less interesting.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)