was the commander of the
troops who guarded the emperor's person. [PRAETORIANI
] This office was instituted by Augustus,
and was at first only military, and had comparatively small power attached
to it (D. C. 52.24
; Suet. Aug. 49
); but under
Tiberius, who made Seianus commander of the praetorian troops, it became of
much greater importance, till at length the power of these praefects became
second only to that of the emperors. (Tac. Ann.
; Aurel. Vict. de
9.) The relation of the praefectus praetorio to the emperor is
compared with that of the magister equitum to the dictator under the
Republic. (Dig. 1
was, as the officer of highest rank, always present at court, the natural
medium through which the emperor issued his orders and carried out his
decisions, although his actual influence would naturally depend mainly on
his personal character. From the reign of Severus to that of Diocletian, the
praefects, like the vizirs of the East, had the [p. 2.477]
superintendence of all departments of the state, the palace, the army,
especially in Italy, the finances, and the law: they also had a court in
which they decided cases (Dig. 12
), mainly as the representative of
the emperor in appeals from the provinces. (Mommsen, Staatsr.
2.932.) Hence the office of praefect of the praetorium was in later times
not confined to military officers; it was filled by Ulpian, Papinian,
Paulus, and other distinguished jurists.
Originally there were two praefects (D. C. 4.10
afterwards sometimes one and sometimes two; fiom the time of Commodus
sometimes three (Lamprid. Commod.
6), and even four.
2.831, 3.) They were as a regular rule
chosen only from the equites (D. C. 52.24
Suet. Tit. 6
4); but from the time of Alexander Severus the
dignity of senator was always joined with their office (Lamprid.
Under Constantine the praefects were deprived of all military command, and
changed into governors of provinces. He appointed four such praefects: the
one (praefectus Orientis) who commonly attended on the imperial court had
the command of Thrace, the whole of the East, and Egypt; the second (pr.
Illyrici) had the command of Illyricum, Macedonia, and Greece, and usually
resided first at Sirmium, afterwards at Thessalonica; the third (pr.
Italiae) of Italy and Africa, residing usually at Milan; the fourth
(praefectus Galliarum), who resided at Trèves, of Gaul, Spain,
and Britain. (Zosimus, 2.33.) These praefects were the proper
representatives of the emperor, and their power extended over all
departments of the state: the army alone was not subject to their
jurisdiction. They were co-ordinate with the praefects of the two capital
cities of Rome and Constantinople. (Walter, Gesch. des röm.
§ § 269, 341; Gibbon, Decline