PILETORIANS was, in the time of the Roman republic, the name of a select cohort which attended the person of the praetor or com anander of a Roman army. &Must (` Catilina,' GO) says that Petreius, finding that Catilina and his followers defended themselves more etoutly than he expected, ordered, as a last expedient, the praetorian cohort to charge the insurgents, and this decided the fate of the battle. In the time of the triumvirate, Octavian and Antony greatly increased the number of the praetorians. Appianus (` Bell. Civ;) says that after the battle of Philippi they dismissed all those soldiers who had served their time, except 8000 men who requested to remain in the service, who were distributed in praetorian cohorts attached to the persona of the triumvirs. After the final overthrow of the republican party, Augustus formed the praetorians into nine cohorts, and Tiberius fixed their station in the capital as guards to his person. (Suetenius, ' August,' 49.) They became in fact, under the emperors, what the regiments of guards or household troops are in the actual monarchies of Europe, a select and privileged body in the army. But besides their
ordinary military duties, they had also the charge of state 'prisoners, and often acted as executioners. The prefect of the przetorium was the commander of the whole body of praetorians. They were all picked men, chosen from Old Latium, Umbria, Etruria, and the older Roman colonies, and they were proud of their origin. (Tacitus, Annal.; iv. 5.) Under Vitellius the praetorian cohorts were increased to sixteen.
(Tacitus, ii. 93.) In the frequent revolutions of the empire the prxtorians acted a conspicuous part, and often determined the fate of an emperor, and the choice of another; as iu later times the janissaries did with regard to the Turkish sultans. Diocletian reduced the number of the praetorians, and Constantine entirely disbanded them.