In Ancient Rome, a province (Latin, provincia, pl. provinciae) was the basic, and until the Tetrarchy (circa 296), largest territorial and administrative unit of the empire's territorial possessions outside of the Italian peninsula. The word province in modern English has its origins in the term used by the Romans.
Provinces were generally governed by politicians of senatorial rank, usually former consuls or former praetors. A later exception was the province of Egypt, incorporated by Augustus after the death of Cleopatra: it was ruled by a governor of equestrian rank only, perhaps as a discouragement to senatorial ambition. This exception was unique, but not contrary to Roman law, as Egypt was considered Augustus' personal property, following the tradition of earlier, Hellenistic kings.
The term provincia originally designated simply a task or duty within the Roman state. Under the Roman Republic, the magistrates were elected to office for a period of one year, and those serving outside the city of Rome, like the consuls on campaign, were assigned a particular "province", an area of authority. The term did not acquire a definite territorial sense until Rome started expanding beyond Italy during the First Punic War, and the first permanent provinces (Sicily in 241 BC and Sardinia in 237 BC) were set up.
At the beginning of each year, the provinces were distributed to future governors by lots or direct appointment. Normally, the provinces where more trouble was expected — either from barbaric invasions or internal rebellions — were given to active or former consuls, men of the greatest prestige and experience, while the rest given to praetors and propraetors.
The distribution of the legions across the provinces was also dependent of the amount of danger that they represented. In 14, for instance, the province of Lusitania had no permanent legion but Germania Inferior, where the Rhine frontier was still not pacified, had a garrison of four legions. These problematic provinces were the most desired by future governors. Problems meant war, and war could be expected to bring plunder, slaves to sell, and other opportunities for enrichment.
List of Republican provinces 241 BC - Sicilia, propraetorial province (senatorial from 27 BC) 231 BC - Corsica et Sardinia, propraetorial province (senatorial from 27 BC) 203 BC - Gallia Cisalpina, propraetorial province (merged with Italy ca. 42 BC) 197 BC - Hispania Citerior and Hispania Ulterior, propraetorial provinces (imperial from 27 BC) 167 BC - Illyricum, propraetorial province (imperial from 27 BC) 146 BC - Macedonia, propraetorial province (senatorial from 27 BC) 146 BC - Africa proconsularis, proconsular province (senatorial from 27 BC) 129 BC - Asia, proconsular province (senatorial from 27 BC) 120 BC - Gallia Transalpina (later Gallia Narbonensis), propraetorial province (senatorial from 27 BC) 74 BC - Bithynia, propraetorial province (senatorial from 27 BC) 74 BC - Cyrenaica et Creta, propraetorial province (senatorial from 27 BC) 66 BC - Corduene (imperial from 27 BC) 64 BC - Cilicia et Cyprus, propraetorial province (senatorial from 27 BC) 64 BC - Syria, propraetorial province (imperial from 27 BC) 51 BC - Gallia Comata (divided in 22 BC) 30 BC - Aegyptus, personal domain of Augustus, getting a special governor styled Praefectus Aegypti 29 BC - Moesia, propraetorial province (imperial from 27 BC)
 Imperial provinces during the Principate In the so-called Augustan Settlement of 27 BC, which established the Roman Empire, the governance of the provinces was regulated. Octavian Caesar, having emerged from the Roman civil wars as the undisputed victor and master of the Roman state, officially laid down his powers, and in theory restored the authority of the Roman Senate. Octavian himself assumed the title "Augustus" and was given to govern, in addition to Egypt, the strategically important provinces of Gaul, Hispania and Syria (including Cilicia and Cyprus). These "imperial provinces" were governed by men (legati Augusti propraetore) appointed solely by the emperor, selected from either the patricians or the equestrian class. They were assisted by equestrian procuratores as chief financial officials. The remaining provinces, usually in the Empire's interior and with weak military forces, often termed "senatorial provinces", were governed by former magistrates for terms of one to two years, who were assisted by quaestores. The system remained flexible however, and in subsequent years provinces would change status as the situation required. In any event, as the centrality of the emperors' position in the administration grew, the practical differences between the "imperial" and "senatorial" provinces diminished.
During the Principate, the number and size of provinces also changed, either through conquest or through the division of existing provinces. The larger or more heavily garrisoned provinces (for example Syria and Moesia) were subdivided into smaller provinces in order to prevent any single governor from holding too much power in his hands.
List of provinces created during the Principate 27 BC - Achaea separated from Macedonia, senatorial propraetorial province
25 BC - Galatia, imperial propraetorial province
22 BC - Gallia Comata divided into Gallia Aquitania, Gallia Belgica, Gallia
Lugdunensis, imperial propraetorial provinces
15 BC - Raetia, imperial procuratorial province
ca. 13 BC - Hispania Ulterior divided into Baetica and Lusitania (senatorial
propraetorial and imperial propraetorial respectively)
12 BC - Germania Magna, lost after 9 AD
6 AD - Iudaea, imperial procuratorial province (renamed Syria Palaestina by
Hadrian, and upgraded to proconsular province).
14 - Alpes Maritimae, imperial procuratorial province
18 - Cappadocia, imperial propraetorial (later proconsular) province
ca. 20-50 - Illyricum divided into Illyricum Superior (Dalmatia) and Illyricum Inferior (Pannonia), imperial proconsular provinces
40 - Mauretania Tingitana and Mauretania Caesariensis, imperial procuratorial provinces
ca. 40 - Noricum, imperial procuratorial province
43 - Britannia, imperial proconsular province
43 - Lycia and Pamphylia, imperial propraetorial province
46 - Thracia, imperial procuratorial province
ca. 47 - Alpes Poeninae, imperial procuratorial province
63 - Alpes Cottiae, imperial procuratorial province
67 - Epirus, imperial procuratorial province
72 - Commagene annexed to Syria
ca. 84 - Germania Superior and Germania Inferior, imperial proconsular provinces
85 - Moesia divided into Moesia Superior and Moesia Inferior, imperial proconsular provinces
105 - Arabia, imperial propraetorial province
107 - Dacia, imperial proconsular province (split into Dacia Superior and Dacia Inferior between 118 – 158)
107 - Pannonia divided into Pannonia Superior and Pannonia Inferior, imperial provinces (proconsular and propraetorial respectively)
ca. 115 - Armenia, Assyria and Mesopotamia, formed by Trajan, abandoned by Hadrian in 118
166 - Tres Daciae formed: Porolissensis, Apulensis and Malvensis, imperial procuratorial provinces
193 - Syria divided into Syria Coele and Syria Phoenicia, imperial provinces (proconsular and propraetorial respectively)
193 - Numidia separated from Africa proconsularis, imperial propraetorial province
ca. 197 - Mesopotamia, imperial praefectorial province
197 (formalized ca. 212) - Britannia divided into Britannia Superior and Britannia Inferior, imperial provinces (proconsular and propraetorial respectively)
214 AD - Osroene
Note that many of the above provinces were under Roman military control or under the rule of Roman clients for a long time before being officially constituted as civil provinces. Only the date of the official formation of the province is marked above, not the date of conquest.
Emperor Diocletian introduced a radical reform known as the Tetrarchy (284-305), with a western and an eastern Augustus or senior emperor, each seconded by a junior emperor (and designated successor) styled Caesar, and each of these four defending and administering a quarter of the Empire. In the 290s, Diocletian divided the Empire anew into almost a hundred provinces, including Italy. Their governors were hierarchically ranked, from the proconsuls of Africa proconsularis and Asia through those governed by consulares and correctores to the praesides. These last were the only ones recruited from the equestrian class. The provinces in turn were grouped into (originally twelve) dioceses, headed usually by a vicarius, who oversaw their affairs. Only the proconsuls and the urban prefect of Rome (and later Constantinople) were exempt from this, and were directly subordinated to the tetrarchs.
Although the Caesars were soon eliminated from the picture, the four administrative resorts were restored in 318 by Emperor Constantine I, in the form of praetorian prefectures, whose holders generally rotated frequently, as in the usual magistracies but without a colleague. Constantine also created a second capital, Nova Roma, known after him as Constantinople, which became the permanent seat of the Eastern government. In Italy itself, Rome ceased to be the imperial residence, Mediolanum (Milan) and later Ravenna being favoured by the emperors. During the 4th century, the administrative structure was modified several times. Provinces and dioceses were split to form new ones, the praetorian prefecture of Illyricum was abolished and reformed, and changed hands between East and West several times. In the end, with the death of Theodosius I in 395, the permanent division of the Empire into Western and Eastern halves was complete.
Detailed information on these arrangements is contained in the Notitia Dignitatum (Record of Offices), a document dating from the early 5th century. It is from this authentic imperial source that we draw most data, as the names of the areas governed and titles of the governors are given there. There are however debates about the source of some data recorded in the Notitia, and it seems clear that some of its own sources are earlier than others.
It is interesting to compare this with the list of military territories under the duces, in charge of border garrisons on so-called limites, and the higher ranking Comites rei militaris, with more mobile forces, and the later, even higher magistri militum.
In the surviving Eastern half, which evolved into what is known as the Byzantine Empire, this administrative subdivision was gradually changed. Justinian I made the first great changes during his great reforms in 534-536 by abolishing, in some provinces, the strict separation of civil and military authority that Diocletian had established. This process was continued on a larger scale with the creation of extraordinary Exarchates in the 580s and culminated with the adoption of the military theme system in the 640s, which replaced the older administrative arrangements entirely.
List of Late Roman provinces
Praetorian prefecture of Galliae In Latin, Gallia was also sometimes used as a general term for all Celtic peoples and their territories, such as all Brythons, including the Germanic and Iberian provinces which also had a population with a Celtic culture. The plural, Galliae in Latin, indicates that all of these are meant, not just Caesar's Gaul (several modern countries).
Diocese of Galliae Galliae covered about half of the Gallic provinces of the early empire:
in what is now northern France roughly the part north of the Loire (called after the capital Lugdunum, modern Lyon) Gallia Lugdunensis I Gallia Lugdenensis II Gallia Lugdunensis III Gallia Lugdunensis IV in Belgium, Luxembourg, the parts of the Netherlands on the left bank (west) of the Rhine Belgica I Gallia Belgica II Germany on the left bank (west) of the Rhine Germania I Germania II the Helvetic tribes (parts of Switzerland): Alpes Poenninae et Graiae Maxima Sequanorum
Diocese of Viennensis Viennensis was named after the city of Vienna (now Vienne), and entirely in present-day France, roughly south of the Loire. It was originally part of Caesar's newly conquered province of Transalpine Gaul, but a separate diocese from the start.
Viennensis Alpes Maritimae Aquitanica I Aquitanica II Novempopulana Narbonensis I Narbonensis II In the fifth century, Viennensis was replaced by a diocese of Septem Provinciae ('7 Provinces') with similar boundaries.
Diocese of Hispaniae Hispania was the name of the whole Iberian Peninsula. It covered Hispania and the westernmost province of Roman Africa:
Baetica Baleares (the Mediterranean islands) Carthaginiensis Tarraconensis Gallaecia Lusitania Mauretania Tingitana or Hispania Nova, in North Africa
Diocese of Britanniae Britanniae was again a plural
Maxima Caesariensis Valentia Britannia Prima Britannia Secunda Flavia Caesariensis
Praetorian prefecture of Italy and Africa (western) Originally there was a single diocese of Italia, but it was eventually split into a northern section and a southern section. The division of Italy into regions had already been established by Aurelian.
Diocese of Italia suburbicaria Suburbicaria indicates proximity to Rome, the Urbs (capital city). It included the islands, not considered actually Italian in Antiquity (hence they were provinces while the peninsular regions still had a superior status), given their different ethnic stock (e.g. Sicily was named after the Siculi) and history of piracy.
Campania Tuscania et Umbria Picenum Suburbicarium Apulia et Calabria Bruttia et Lucania Samnium Valeria Corsica Sicilia Sardinia
Diocese of Italia annonaria Annonaria refers to a reliance on the area for the provisioning of Rome. It encompassed northern Italy and Raetia.
Venetia and Istria Aemilia Liguria Flaminia and Picenum Annonarium Alpes Cottiae Raetia I Raetia II
Diocese of Africa Africa included the central part of Roman North Africa:
Africa proconsularis or Zeugitana Byzacena Mauretania Caesariensis Numidia Tripolitania
Praetorian Prefecture of Illyricum The Prefecture of Illyricum was named after the former province of Illyricum. It originally included two dioceses, the Diocese of Pannoniae and the Diocese of Moesiae. The Diocese of Moesiae was later split into two dioceses: the Diocese of Macedonia and the Diocese of Dacia.
Diocese of Pannonia Pannonia was one of the two dioceses in the eastern quarters of the Tetrarchy not belonging to the cultural Greek half of the empire (the other was Dacia); It was transferred to the western empire when Theodosius I fixed the final split of the two empires in 395.
Dalmatia Noricum mediterraneum Noricum ripensis Pannonia Prima Pannonia Secunda Savia Valeria ripensis
Diocese of Dacia The Dacians had lived in the Transylvania area, annexed to the Empire by Trajan. However, during the invasions of the third century Dacia was largely abandoned. Some inhabitants evacuated from the abandoned province were settled on the south side of the Danube and their new homeland renamed Dacia accordingly, in order to diminish the impact that abandoning the original Dacia had on the Empire's prestige. The diocese was transferred to the western empire in 384 by Theodosius I, probably in partial compensation to the empress Justina for his recognition of the usurpation of Magnus Maximus in Britannia, Gaul and Hispania.
Dacia mediterranea Moesia I Praevalitana Dardania Dacia ripensis
Diocese of Macedonia The Diocese of Macedonia was transferred to the western empire in 384 by Theodosius I, probably in partial compensation to the empress Justina for his recognition of the usurpation of Magnus Maximus in Britannia, Gaul and Hispania.
Macedonia Prima Macedonia Salutaris (or Macedonia Secunda) Thessalia Epirus vetus Epirus nova Achaea Creta
Praetorian Prefecture of Oriens As the rich home territory of the eastern emperor, the Oriens ("East") prefecture would persist as the core of the Byzantine Empire long after the fall of Rome. Its praetorian prefect would be the last to survive, but his office was transformed into an essentially internal minister.
Diocese of Thrace Thrace was the eastern-most corner of the Balkans (the only part outside the Illyricum prefecture) and the European hinterland of Constantinople.
Europa Thracia Haemimontium Rhodope Moesia II Scythia
Diocese of Asiana Asia (or Asia Minor) in Antiquity stood for Anatolia. This diocese (the name means 'the Asian ones') centred on the earlier Roman province of Asia, and only covered the rich western part of the peninsula, mainly near the Aegean Sea.
Asia Hellespontus (i.e. near the Sea of Marmara, so closest to Greece) Pamphylia Caria Lydia Lycia Lycaonia Pisidia Phrygia Pacatiana Phrygia Salutaria and the adjoining (now mostly Greek) Aegean islands in the aptly named province Insulae
Diocese of Pontus Pontus is Latinized from Greek Pontos: the name of a Hellenistic kingdom derived from Pontos (Euxinos), i.e. the (Black) Sea, earlier used for a major Hellenistic kingdom.
It mainly contains parts of Asia minor near those coasts (as well as the mountainous centre), but also includes the north of very variable border with Rome's enemy Parthia/Persia.
Bithynia Galatia Paphlagonia Honorias Galatia Salutaris Cappadocia I Cappadocia II Helenopontus Pontus Polemoniacus Armenia I Armenia II
Diocese of Oriens The Eastern diocese shares its geographic name with the prefecture, even after it lost its rich part, Egypt, becoming a separate diocese; but militarily crucial on the Persian (Sassanid) border and unruly desert tribes.
It comprised mainly the modern Arabic Machrak (Syria, Lebanon, Iraq, Israel, the Palestinian Territories and Jordan) except for the desert hinterland:
Iudaea Province (after the Romans crushed Bar Kokhba's revolt they renamed it Palestina): Palestina I Palestina II Palestina Salutaris Syria Syria Salutaris Phoenicia Phoenicia Libani Eufratensis Osroene Mesopotamia Arabia Further it contained the southeastern coast of Asia Minor and the close island of Cyprus
Cilicia I Cilicia II Isauria Corduene Cyprus
Diocese of Aegyptus This diocese, comprising north eastern Africa — mainly Egypt, the rich granary and traditional personal domain of the emperors — was the only diocese that was not under a vicarius, but whose head retained the unique title of Praefectus Augustalis. It was created by a split of the diocese of Oriens.
All but one, the civilian governors were of the modest rank of Praeses provinciae.
Aegyptus came to designate Lower Egypt around Alexandria. Originally it was named Aegyptus Iovia (from Jupiter, for the Augustus Diocletian). Later it was divided into two provinces Augustamnica was the remainder of Lower Egypt, together with the eastern part of the Nile delta (13 'cities') - the only Egyptian province under a Corrector, a lower ranking governor. Originally it was named Aegyptus Herculia (for Diocletian's junior, the Caesar; with ancient Memphis). Later it was divided in two provinces Thebais was Upper Egypt. Nubia south of Philae had been abandoned to tribal people. Later it was divided into two provinces, Superior and Inferior. Arcadia (also Arcadia Ægypti; not Arcadia in Greece)