PRÆFECT OF THE PRÆTORIUM, the leader of the pretorian bands destined for the emperor's guards, consisting, according to Dion, of 10,000 men. This officer, according to Suetonius, was instituted by Augustus, and usually taken from among the knights.
By the favour of the emperors his power grew very considerable; to reduce which, Constantine divided the prefecture of the prætorium into four prefectures, and each of these again he subdivided into civil and military departments, though the name was only reserved to him who was invested with the civil authority, and that of comes belli given him who commanded the cohorts.