Administrative Subdivisions of the Roman Empire

The Roman Empire developed over centuries and saw frequent shifts in territory. Administrative subdivisions were institutionalized only in the late Roman era. was divided into provinces led by senatorial statesmen (usually consuls or praetors).

History

Republic of Rome

Initially, the Roman provinciae (singular provincia) were ministerial roles rather than administrations. Some of these roles involved regional governance, but others represented tasking a military commander with conquering a region not yet under imperial rule, and still others were administrative roles like the treasury. Similarly, a region under imperial rule was not necessarily assigned a provinciae. Finally, many provinciae were temporary measures.

In 122 BC, tribune Gaius Sempronius Gracchus pushed reforms requiring that provinciae be selected before consular elections. Because the positions had to be established about 6 months ahead of when a consul would actually be sent, temporary provinciae became ineffective.

Concurrently, the expansion of the empire created more provinciae than could be filled with consuls. It became common for praetors to be granted a promagistrate (pro magistratu), essentially an indefinite prorogation of the post. They either led with the authority of a praetor (pro praetore) or a consul (pro consule).

Altogether, there was a rapid consolidation of power within and across the provinces. This led directly to the fall of the republic, and the rise of the emperor.

Imperial Rome

Augustus personally held most of the provinciae; these became known as imperial provinces. He appointed legatus Augusti pro praetore to administer each in his absence. The remainder are known as senatorial provinces. (Italy itself was treated specially, subdivided into 11 regiones.)

In the 290s, Diocletian reorganized the empire into about 100 provinces under twelve dioceses. Deputies (vicarius, plural vicarii) were appointed to administer them, though were subordinate to the tetrarchs and praetorian prefects.

Only the urban provinces of Rome and Constantinople were not placed under a deputy; they were directly ruled by the tetrarchs.

Generally, Gaul and Dacia also did not have deputies because the prefects administered from those diocese.

Eastern Roman Empire

Roman political structures continued under the Byzantines until Justinian I reconquered a substantial portion of the former western empire and dissolved the dioceses.

Provinces

At the time of Augustus (i.e., died 14 CE), the senatorial provinces were:

• Achaia (alt. Achaea)
• Africa Proconsular
• Asia
• Baetica
• Bithynia et Pontus
• Corsica et Sardinia
• Creta et Cyrenaica
• Gallia Narbonensis
• Macedonia

And the imperial provinces were:

• Aegyptus
• Cilicia et Cyprus
• Dalmatia
• Galatia
• Gallia Aquitania
• Gallia Belgica
• Gallia Lugdunensis
• Hispania Tarraconensis
• Judaea
• Lusitania
• Moesia Inferior
• Moesia Superior
• Noricum
• Pannonia Inferior
• Pannonia Superior
• Raetia
• Silicia
• Syria

(Note that 'conquer' and 'seize' mean a sovereign state, whereas 'annex' means a Roman client state.)

Augustus had conquered the Vallenses, a group of Alpine Gallic tribes. Between the reigns of Claudius and Nero, this territory was reorganized into four provinces: Alpes Graiae, Alpes Poeninae, Alpes Cottiae, and Alpes Maritimae. Eventually the first two were merged into Alpes Graiae et Poeninae.

The kingdom of Cappadocia was conquered in 17 CE and reorganized into a province. Nero conquered the kingdom of Pontus in 62 CE and annexed that territory into the province of Cappadocia.

Ptolemy, king of Mauretania and a vassal of Rome, was executed in 40 CE by Caligula. His kingdom was annexed and partitioned into the provinces of Mauretania Caesariensis and Mauretania Tingitana.

The Lycian League was annexed in 43 CE by Claudius. Vespasian split the southern portion of Galatia to establish the province of Lycia et Pamphylia in 74 CE.

The Sapaean or Thracian Kingdom was annexed in 46 CE by Claudius and reorganized into the province of Thracia.

The conquest of Britons, which began under Julius Caesar, was 'completed' in 43 CE by Claudius. The province of Britannia was established and pushed northwards until stalling against the Caledonians. It was partitioned into Britannia Inferior and Inferior Superior in 197 CE by Septimius Severus.

In 72 CE, Vespasian conquered the kingdom of Commagene and seized part of Armenia, annexing these territories into the province of Syria. Between the reigns of Vespasian and Domitian, several more client states were annexed into the province (e.g., the territories held by Herod Agrippa II, who died without an heir).

The territories conquered by Domitian were reorganized as Germania Inferior and Germania Superior.

Trajan substantially expanded the empire in several direction:

• By 106 CE, he conquered the Dacian Kingdom and reorganized it into the province of Dacia.
• As part of the larger Roman-Parthian Wars, he pushed into the Parthian Empire and conquered the remainder of Armenia. Short-lived provinces of Armenia, Mesopotamia, and Assyria were established. Before long however, the kingdom of Armenia was reestablished as a client state and Parthian territories were abandoned.
• He annexed the Nabataean Kingdom in 106 CE and reorganized it into the province of Arabia Petraea.

Additionally, Trajan split off the northern portion of Macedonia into the senatorial province of Epirus.

Altogether, Trajan's reign is a notable point in imperial administration; see here for additional details.

Note that Dacia was partitioned and reorganized repeatedly (Dacia Inferior and Dacia Superior; then Dacia Malvensis, Dacia Apulensis, and Dacia Porolissensis). These reforms were pursued because the territory was frequently threatened by the Marcomanni and Quadi. Finally, Dacia was abandoned to the Goths in 275 CE by Aurelian. A northern portion of Moesia Superior was split off to create Dacia Aureliana for the refugees.

In addition to partitioning Britannia, Septimius Severus partitioned Syria into Syria Coele and Syria Phoenice, and split off the western portion of the senatorial province of Africa Proconsular to establish the imperial province of Numidia.

The kingdom of Osroene was conquered in 213 CE by Caracalla and reorganized into the province of Osroene.

Diocese

• Africa (Africae)

• Asia (Asiana)

• Britain (Britanniae)

• Dacia (Daciae)

• the East (Orientis)

• Egypt (Aegypti)

• Gaul (Galliae)

• Northern Italy (Italiae Annonariae)

• Southern Italy (Italy Suburbicariae)

• Macedonia

• Pannonia (Pannoniarum, literally "the Pannonias")

• Pontus (Pontica)

• Spain (Hispania)

• Thracia (Thraciae)

• Vienna (Viennensis; alternatively the Seven Provinces, Septem Provinciarum)

CategoryRicottone