theme system. Elements of the prefecture's administrative apparatus, however, are documented to have survived in the Byzantine Empire
until the first half of the 9th century.
History
Map of the Roman Empire under the Tetrarchy, showing the dioceses and the four tetrarchs' zones of control.
The office of the
Constantine I established the praetorian prefectures as definite territorial administrations as early as 318, or in 324, after his victory over Licinius.[2]
During the
Constantine I.[4] In 317 a third prefect was added in Gaul for Constantine's son Crispus. After his execution in 326 this prefect was retained. From 317 there were never less than three, and for years 347–361, 374–379 and 388–391, four, with the addition of a prefecture for Illyricum, although in the last two years it comprised only the dioceses of Dacia and Macedonia which would be the permanent territory from then on after restoration in 395.
The administrative divisions of the Roman Empire in 395 AD
Following Constantine's victory over Licinius and the unification of the Empire under his rule, the office was transformed. The prefect's military duties were removed by the creation of the purely military offices of the
magister peditum and magister equitum ("Master of the Foot/Horse"), and the establishment of the magister officiorum as the powerful head of the palatine bureaucracy and the civil service at large provided a counterbalance to the prefect's power.[5][6] These reforms were the result of both the lack of officials suitable for the prefect's wide-ranging tasks,[7] and of the desire to reduce the potential challenge to the emperor's authority posed by the over-mighty prefect.[8] The office of the prefect was consequently converted into a purely civilian administrative one, albeit retaining the highest position in the imperial hierarchy, immediately below the emperor himself.[9] Another important departure from tetrarchic practice was the increase in the number of holders: no less than five prefects are attested for ca. 332. This development is likely related to Constantine's giving his four sons specific territories to administer, envisioning a partition of imperial authority among them following his death. In this, the origins of the later territorial prefectures may be detected.[10]
The four prefectures of the Roman Empire, as they appear in the Notitia Dignitatum, ca. 400 AD.
After Constantine's death in 337, his three surviving sons partitioned the Empire between them. As each new Augustus had his own praetorian prefect, this division created the first of what would gradually become the permanent praetorian prefectures: the western
Diocese of Illyricum") from the prefecture of Illyricum and its incorporation into the prefecture of Italy in 379. The diocese of Italy was in practice divided into two: of Italy in the north, and suburbicarian ("under the City
") Italy in the south including Sicily, Corsica and Sardinia. There were no vicars appointed to the dioceses of Gaul and Dacia, because the praetorian prefects of Gaul and Illyricum were resident. When the prefect of Italy was in Milan, a vicar for Illyricum was appointed to reside in Sirmium; when the prefect resided in Sirmium, the post was lapsed, and a vicar was appointed to reside in Milan in place of the prefect.
In the course of the 5th century, the Western Empire was overrun by the
theme system, with the prefect in Constantinople possibly in a supervisory capability, until the 840s.[14]
Authority and powers of the prefect
The insignia of the praetorian prefect of Illyricum, as depicted in the Notitia Dignitatum: the ivory inkwell and pen case (theca), the codicil of appointment to the office on a blue cloth-covered table, and the state carriage.[15]
Originally, the praetorian prefects were drawn from the
equestrian class. Constantine's reforms entailed the reservation of this office for members of the senatorial class, and its prestige and authority were raised to the highest level, so that contemporary writers refer to it as the "supreme office".[16] In the divided Empire, the two senior prefects were those of the East and of Italy, residing in the courts of the two emperors and acting effectively as their first ministers, while the prefects of Illyricum and Gaul held a more junior position.[17]
The prefects held wide-ranging control over most aspects of the administrative machinery of their provinces, and only the magister officiorum rivalled them in power. The prefects fulfilled the roles of supreme administrative and juridical official, already present from the time of Septimius Severus, and that of chief financial official, responsible for the state budget. In their capacity as judges, they had the right to pass judgment instead of the emperor (vice sacra), and, unlike lower governors, their decision could not be appealed.
Their departments were divided in two major categories: the schola excerptorum, which supervised administrative and judicial affairs, and the scriniarii, overseeing the financial sector.[18]
Kelly, Christopher (2006). "Bureaucracy and Government". In Lenski, Noel (ed.). The Cambridge Companion to the Age of Constantine. Cambridge University Press.
