Praetorian prefecture

The praetorian prefecture (Latin: praefectura praetorio; in Greek variously named ἐπαρχότης τῶν πραιτωρίων or ὑπαρχία τῶν πραιτωρίων) was the largest administrative division of the late Roman Empire, above the mid-level dioceses and the low-level provinces. Praetorian prefectures originated in the reign of Constantine I (r. 306-337), reaching their more or less final form in the last third of the 4th century and surviving until the 7th century, when the reforms of Heraclius diminished the prefecture's power, and the Muslim conquests forced the East Roman Empire to adopt the new 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.


Tetrarchy map3
Map of the Roman Empire under the Tetrarchy, showing the dioceses and the four Tetrarchs' zones of control.

The office of the praetorian prefect had a long history dating back to the origins of the Roman Empire: initially, its two holders were the commanders of the Praetorian Guard, but gradually, they became the emperor's chief aides, and amassed considerable administrative and judicial responsibilities. The exact process of transformation to the chief civilian administrator of a specific territorial circumscription is still unclear.[1] A common misconception, based on Zosimus, is that 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 Tetrarchy, when the number of holders of the imperial office multiplied (two senior emperors, the Augusti, and two junior colleagues, the Caesares), there is evidence for the existence of only two prefects at each time, presumably assigned to each of the Augusti. At that stage, the prefect's power was still immense. In the words of A.H.M. Jones, he was "a kind of grand vizier, the emperor's second in command, wielding a wide authority in almost every sphere of government, military and judicial, financial and general administration. He was the emperor’s chief of staff, adjutant-general, and quartermaster-general...".[3] Following Diocletian's abdication in 305, civil war erupted among the various co-emperors, during which time each of the contenders appointed his own prefect, a pattern carried on during the period where the Empire was shared between Licinius and 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 347-61, 74-79 and 88-91, four, with the addition of 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.

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]

Roman Empire with praetorian prefectures in 400 AD
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 prefecture of Gaul (dioceses of Gaul,Viennensis, Hispania and Britain), the central prefecture of Italy, Illyricum and Africa (dioceses of Italy, Africa, Pannonia, Dacia and Macedonia) and the prefecture of the East (dioceses of Thrace, Asia, Pontus, Oriens). Egypt was part of the diocese of Oriens until 370 or 381. With the creation of the separate prefecture of Illyricum (dioceses of Pannonia, Dacia and Macedonia) in 347 until 361, and despite the occasional abolition of the latter, the picture that appears in the early 5th-century Notitia dignitatum ("list of dignities") was complete. The only major change was the removal of the diocese of Pannonia (renamed to "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 invasions of Germanic tribes. However, the prefecture of Italy was retained by the new Ostrogothic Kingdom, which was still de jure part of the Empire, and Ostrogothic king Theodoric the Great even re-established the prefecture of Gaul in the small portion of Gaul he conquered in the 510s. After the reconquest of Northern Africa by the Eastern Empire during the Vandalic War of 533–534, the new provinces were grouped by emperor Justinian I into a new praetorian prefecture of Africa, which would later be transformed into the Exarchate of Africa. The praetorian prefecture of Italy was also re-established after the end of the Gothic War, before it too evolved into an exarchate. In the East, the prefectures would continue to function until the mid-7th century, when the loss of most eastern provinces to the Muslim conquest and of the Balkans to Slavic tribes led to the creation of the Theme system. In the meantime, however, reforms under Heraclius had stripped the prefect from a number of his subordinate financial bureaux, which were set up as independent departments under logothetes.[11] The last time the prefect of the East is directly attested comes from a law of 629.[12] According to some scholars however, traces of the system survived into the early 9th century: Ernst Stein demonstrated that some aspects of the Illyrian prefecture survived in the administration of Thessalonica,[13] while John Haldon, based on sigillographic evidence and references in the Byzantine Taktika, has documented the survival of the earlier civilian provincial administration within the theme system, with the prefect in Constantinople possibly in a supervisory capability, until the 840s.[14]

Authority and powers of the prefect

Notitia dignitatum - insignia praefecti praetorio per illyricum
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]


  1. ^ Kelly (2006), p. 185
  2. ^ Morrison (2007), p. 190
  3. ^ Jones (1964), p. 371
  4. ^ Kelly (2006), p. 186
  5. ^ Kelly (2006), pp. 187–188
  6. ^ Kazhdan (1991), p. 1267
  7. ^ Jones (1964), p. 101
  8. ^ Kelly (2006), p. 187
  9. ^ Morrison (2007), pp. 177–179
  10. ^ Kelly (2006), pp. 186–187
  11. ^ Haldon (1997), pp. 18–190
  12. ^ Haldon (1997), p. 195
  13. ^ Kazhdan (1991), pp. 987, 1710
  14. ^ Haldon (1997), pp. 195–207
  15. ^ Kelly (2004), p. 41
  16. ^ Morrison (2007), p. 177
  17. ^ Bury, p. 27
  18. ^ Kazhdan (1991), 1710


  • Notitia dignitatum
  • Bury, John Bagnell (1923). History of the Later Roman Empire, Volume I, Chapter II. Macmillan & Co., Ltd.
  • Haldon, John F. (1997). Byzantium in the Seventh Century: The Transformation of a Culture. Cambridge University Press. ISBN 978-0-521-31917-1.
  • Jones, A.H.M. (1964). The Later Roman Empire, 284-602: A Social, Economic, and Administrative Survey.
  • Kazhdan, Alexander, ed. (1991). Oxford Dictionary of Byzantium. Oxford University Press. ISBN 978-0-19-504652-6.
  • Kelly, Christopher (2006). "Bureaucracy and Government". In Lenski, Noel (ed.). The Cambridge Companion to the Age of Constantine. Cambridge University Press. ISBN 978-0-521-52157-4.
  • Morrison, Cécile, ed. (2007). Le Monde byzantin, tome 1: L'Empire romain d'Orient, 330-641 (in Greek). Athens: Polis Editions. ISBN 978-960-435-134-3.
Dacia Mediterranea

Dacia Mediterranea (Mediterranean Dacia; Greek: Επαρχία Δακίας Μεσογείου, Eparchia Dakias Mesogeiou) was a late Roman province, split off from the former Dacia Aureliana by Roman emperor Diocletian (284-305). Serdica (or Sardica; later Sradetz or Sredets, now Sofia) was the province capital.

Scholars have different opinions regarding the date and circumstances of the foundation of Dacia Mediterranea as a separate province.

Diocese of Africa

The Diocese of Africa (Latin: Dioecesis Africae) was a diocese of the later Roman Empire, incorporating the provinces of North Africa, except Mauretania Tingitana. Its seat was at Carthage, and it was subordinate to the Praetorian prefecture of Italy.

The diocese included the provinces of Africa proconsularis (also known as Zeugitana), Byzacena, Mauretania Sitifensis, Mauretania Caesariensis, Numidia Cirtensis, Numidia Militiana and Tripolitania. In current geo-political terms, the Diocese of Africa included the entire coastline of Algeria and Tunisia, with some mountainous hinterlands, plus the western half of Libya's coastline.

The diocese existed from the time of the Diocletianian and Constantinian reforms in the last years of the 3rd century until it was overrun by the Vandals in the 430s. The provincial organization were retained under the Vandals, and after their defeat and the reconquest of Africa by the Eastern Roman Empire in the Vandalic War, they were grouped anew, but this time in a praetorian prefecture.

Diocese of Asia

The Diocese of Asia (Latin: Dioecesis Asiana, Greek: Διοίκησις Ασίας/Ασιανής) was a diocese of the later Roman Empire, incorporating the provinces of western Asia Minor and the islands of the eastern Aegean Sea. The diocese was established after the reforms of Diocletian, was subordinate to the Praetorian prefecture of the East, and was abolished during the reforms of Justinian I in 535.

It was one of the most populous and wealthy dioceses of the Empire, and included 11 provinces: Asia, Hellespontus, Pamphylia, Caria, Lydia, Lycia, Lycaonia, Pisidia, Phrygia Pacatiana, Phrygia Salutaria and Insulae.

Diocese of Dacia

The Diocese of Dacia (Latin: Dioecesis Daciae) was a diocese of the later Roman Empire, in the area of modern western Bulgaria, central Serbia, Montenegro, northern Albania and northern Republic of Macedonia. It was subordinate to the Praetorian prefecture of Illyricum. Its capital was at Serdica (modern Sofia).

Diocese of Egypt

The Diocese of Egypt (Latin: Dioecesis Aegypti, Greek: Διοίκηση Αιγύπτου) was a diocese of the later Roman Empire (from 395 the Eastern Roman Empire), incorporating the provinces of Egypt and Cyrenaica. Its capital was at Alexandria, and its governor had the unique title of praefectus augustalis ("Augustal Prefect", of the rank vir spectabilis; previously the governor of the imperial 'crown domain' province Egypt) instead of the ordinary vicarius. The diocese was initially part of the Diocese of the East, but in ca. 380, it became a separate entity, which lasted until its territories were finally overrun by the Muslim conquest of Egypt in the 640s.

Diocese of Gaul

See Christianity in Gaul for the 4th-century ecclesiastical dioceses in Roman GaulThe Diocese of Gaul (Latin: Dioecesis Galliarum, "diocese of the Gaul [province]s") was a diocese of the later Roman Empire, under the praetorian prefecture of Gaul. It encompassed northern and eastern Gaul, that is, modern France north and east of the Loire, including the Low Countries and modern Germany west of the Rhine.

The diocese comprised the following provinces: Gallia Lugdunensis I, Gallia Lugdunensis II, Gallia Lugdunensis III, Gallia Lugdunensis IV (Senonia), Belgica I, Belgica II, Germania I, Germania II, Alpes Poenninae et Graiae and Maxima Sequanorum.

Diocese of Macedonia

The Diocese of Macedonia (Latin: Dioecesis Macedoniae, Greek: Διοίκησις Μακεδονίας) was a diocese of the later Roman Empire, forming part of the praetorian prefecture of Illyricum. Its administrative centre was Thessaloniki.

Diocese of Pannonia

The Diocese of Pannonia (Latin: Dioecesis Pannoniarum, lit. "Diocese of the Pannonias"), from 395 known as the Diocese of Illyricum, was a diocese of the Late Roman Empire. The seat of the vicarius (governor of the diocese) was Sirmium.

Diocese of Thrace

The Diocese of Thrace (Latin: Dioecesis Thraciae, Greek: Διοίκησις Θράκης) was a diocese of the later Roman Empire, incorporating the provinces of the eastern Balkan Peninsula (comprising territories in modern south-eastern Romania, central and eastern Bulgaria, and Greek and Turkish Thrace). Philippopolis (modern Plovdiv, in Bulgaria) was the capital.

The diocese was established as part of the reforms of Diocletian and Constantine the Great, and was headed by a vicarius subordinate to the praetorian prefecture of the East. As outlined in the Notitia Dignitatum of ca. 400, the diocese included the provinces of Europa, Thracia, Haemimontus, Rhodope, Moesia II and Scythia Minor.

In May 535, with Novel 26, Justinian I abolished the Diocese of Thrace. Its vicarius retained his rank of vir spectabilis and received the new title of praetor Justinianus, uniting in his hand both civil and military authority over the provinces of the former diocese, in a crucial departure from the strict separation of authority from the Diocletianian system. A year later, in May 536, the two Danubian provinces, Moesia Inferior and Scythia, where detached to form, along with other provinces, the quaestura exercitus.

Europa (Roman province)

Europa was a Roman province within the Diocese of Thrace.


Haemimontus (Greek: ἐπαρχία Αἱμίμοντος) was a late Roman and early Byzantine province, situated in northeastern Thrace. It was subordinate to the Diocese of Thrace and to the praetorian prefecture of the East. Its capital was Adrianople, and it was headed by a praeses. The province was superseded by the Theme of Thrace during the 7th century, but survived as an Orthodox ecclesiastical metropolis until late Byzantine times.

List of Late Roman provinces

This article presents a list of Roman provinces in the Late Roman Empire, as found in the Notitia Dignitatum.

Praetorian prefecture of Africa

The praetorian prefecture of Africa (Latin: praefectura praetorio Africae) was a major administrative division of the Eastern Roman Empire located in the Maghreb. With its seat centered at Carthage, it was established after the reconquest of northwestern Africa from the Vandals in 533–534 by the Byzantine Emperor Justinian I. It continued to exist until the late 580s, when it was replaced by the Exarchate of Africa.

Praetorian prefecture of Gaul

The Praetorian Prefecture of Gaul (Latin: praefectura praetorio Galliarum) was one of four large prefectures into which the Late Roman Empire was divided.

Praetorian prefecture of Illyricum

The praetorian prefecture of Illyricum (Latin: praefectura praetorio per Illyricum; Greek: ἐπαρχότης/ὑπαρχία [τῶν πραιτωρίων] τοῦ Ἰλλυρικοῦ, also termed simply the Prefecture of Illyricum) was one of four praetorian prefectures into which the Late Roman Empire was divided.

The administrative centre of the prefecture was Sirmium (375-379), and, after 379, Thessalonica. It took its name from the older province of Illyricum, which in turn was named after ancient Illyria, and in its greatest expanse encompassed Pannonia, Noricum, Crete, and most of the Balkan peninsula except for Thrace.

Praetorian prefecture of Italy

The praetorian prefecture of Italy (Latin: Praefectura praetorio Italiae, in its full form (until 356) praefectura praetorio Italiae, Illyrici et Africae) was one of four Praetorian prefectures into which the Late Roman Empire was divided. It comprised the Italian peninsula, the Western Balkans, the Danubian provinces and parts of North Africa. The Prefecture's seat moved from Rome to Milan and finally, Ravenna.

Praetorian prefecture of the East

The praetorian prefecture of the East, or of the Orient (Latin: praefectura praetorio Orientis, Greek: ἐπαρχότης/ὑπαρχία τῶν πραιτωρίων τῆς ἀνατολῆς) was one of four large praetorian prefectures into which the Late Roman Empire was divided. As it comprised the larger part of the Eastern Roman Empire, and its seat was at Constantinople, the praetorian prefect was the second most powerful man in the East, after the Emperor, in essence serving as his first minister.

Scythia Minor

Scythia Minor or Lesser Scythia (Greek: Μικρά Σκυθία, Mikrá Skythia) was in ancient times the region surrounded by the Danube at the north and west and the Black Sea at the east, roughly corresponding to today's Dobrogea, with a part in Romania, and a part in Bulgaria.

By the 7th century BC, several Greek colonies were built on its Black Sea shore, and the earliest written Greek reports state that the lands were inhabited by Thracians, reidentified in time as Getae and then Dacians. During later times, the area also witnessed Celtic and Scythian invasions. It was part of the kingdom of Dacia for a period, after which the region was conquered by the Roman Empire, becoming part of the province of Moesia Inferior. With Diocletian's reforms, it was split from Moesia as a separate province of "Scythia", being part of the Diocese of Thrace. After the partition of the Empire in 395, the province was retained by the Byzantine Empire until it was annexed by the Bulgars following the Battle of Ongal.

One of the most famous descriptions of the region is found in Herodotus in the 5th century BC, who identified as Scythia the region starting north of the Danube delta.

In a 2nd-century BC inscription recording a decree of Histria honouring Agathocles, the region already was named Scythia. While the earliest usage of the name "Lesser Scythia" (Mikrá Skythia) in literature is found in Strabo's at the end of the 1st-century BC Geography.

Septem Provinciae

The Diocese of the Seven Provinces (Latin: Dioecesis Septem Provinciarum), originally called the Diocese of Vienne (Latin: Dioecesis Viennensis) after the city of Vienna (modern Vienne), was a diocese of the later Roman Empire, under the praetorian prefecture of Gaul. It encompassed southern and western Gaul (Aquitania and Gallia Narbonensis), that is, modern France south and west of the Loire, including Provence.

The diocese comprised the following provinces: Aquitanica I, Aquitanica II, Novempopulana (Aquitanica III), Narbonensis I, Narbonensis II, Viennensis and Alpes Maritimae.

Late Roman provinces (4th–7th centuries AD)
Designations for types of administrative territorial entities

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