List of Roman provinces

==Roman provinces in AD 120==
Achaea
Aegyptus
Africa
Alpes Cottiae
Alpes Maritimae
Alpes Poenninae
Arabia Petraea
Armenia Inferior
Asia
Assyria
Bithynia
Britannia
Cappadocia
Cilicia
Commagene
Corduene
Corsica et Sardinia
Creta et Cyrenaica
Cyprus
Dacia
Dalmatia | Epirus | Galatia | Gallia Aquitania | Gallia Belgica | Gallia Lugdunensis | Gallia Narbonensis | Germania Inferior | Germania Superior | Hispania Baetica | Hispania Lusitania | Hispania Tarraconensis | Italia | Iudaea | Lycaonia | Lycia | Macedonia | Mauretania Caesariensis | Mauretania Tingitana | Moesia | Noricum | Numidia | Osroene | Pannonia | Pamphylia | Pisidia | Pontus | Raetia | Sicilia | Sophene | Syria | Thracia
==List of Roman Provinces - AD 300 to AD 476==
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.
The scheme was not to last in detail, but 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, and each of these two cities had its own extraordinary governor or Praefectus Urbi. In general, between the acclamation of Diocletian and the formal end of the western Empire in 476, the Empire was recognised as being divided into two, with separate Emperors for the Eastern and Western halves.
Diocletian set up twelve dioceses, each governed by a Vicarius. Three more were created by splits in the fourth century: in the west, Italia was split in two, and in the east Egypt was detached from Oriens.
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. 
This administrative subdivision was later changed in Byzantine times, with the creation of extraordinary Exarchs and originally military Themas.
===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 Britons, while the Germanic and Iberian provinces had a mixed, largely Celtic population. The plural, Galliae in Latin, indicates that all of these are meant, not just Caesar's Gaul (several modern countries).
====Diocese of 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
**Gallia 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 Penninae et Graiae
**Maxima Sequanorum
====Diocese of Viennensis ====
Named after the city of Vienna (now Vienne), and entirely in present-day France, roughly south of the Loire; originally part of Caesar's newly conquered province of Transalpine Gaul, but a separate diocesis from the start.
*Viennensis
*Alpes Maritimae
*Gallia Aquitania/Aquitanica I
* Aquitanica II
*Novempopulana
*Gallia Narbonensis/Narbonnensis 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 (Portugal, north of the Douro river and Galicia/Spain)
*Lusitania, Portugal (south of the Douro river) and neighbouring parts of Spanish Extremadura
*Mauretania Tingitana or Hispania Nova, in [[North Africa
====Diocese of Britanniae====
Again a plural
*Maxima Caesariensis
*Valentia (Roman Britain)
*Britannia Prima
*Britannia Secunda
*Flavia Caesariensis
===Praetorian prefecture of Italy and Africa (western)===
*Originally there was a single diocese of Italia, but it got split north-south.
====Diocese of Italia suburbicaria====
The name indicates proximity to Rome, 'the' Urbs (capital city).
*Campania
*Tuscania et Umbria
*Picenum Suburbicarium
*Apulia et Calabria
*Bruttia et Lucania
*Samnium
*Valeria
*Corsica
*Sicilia
*Sardinia
====Diocese of Italia annonaria====
This name refers to reliance on the area for the provisioning of Rome; it included the islands, not considered actually Italian in Antiquity (hence 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.
*Venetia and Istria
*Aemilia
*Liguria
*Flaminia and Picenum Annonarium
*Alpes Cottiae
*Raetia I
*Raetia II
====Diocese of Africa====
Included the central part of Roman North Africa:
*Africa proconsularis
*Byzacena
*Mauretania Caesariensis
*Numidia
*Tripolitania
===Prefecture of Illyricum===
The Prefecture of Illyricum was named after the former province of Illyricum.
The Prefecture of Illyricum 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 last conquest, the Diocese of Dacia.
====Diocese of Pannonia====
This 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), and 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
*Pannonia 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. Inhabitants evacuated from the abandoned province were settled on the south side of the Danube and their new homeland renamed Dacia accordingly. 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)
*Thessaly|Thessalia
*Epirus vetus
*Epirus nova
*Achaea
*Crete
===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 pretorian prefect would be the last to survive, but his office was transformed into an essentially internal minister.
====Diocese of Thrace====
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====
The name for this 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.
Indeed 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, Palestine/-Israel and Jordan) except for the desert hinterland:
*Iudaea Province (after the Romans crushed Bar Kokhba's revolt they renamed it into 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
*Cyprus
====Diocese of Aegyptus====
This diocesis, 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 specifically came to designate Lower Egypt, previously two provinces, named after the pagan titles of the two emperors under Diocletian:
*Aegyptus Iovia (from Jupiter, for the Augustus; with the metropole Alexandria) and
*Aegyptus Herculia (for his junior, the Caesar; with ancient Memphis)
*Augustamnica, part of the Nile delta (13 'cities') - the only Egyptian province under a Corrector, a lower ranking governor;
*Thebais, Upper Egypt; Nubia south of Philae had been abandoned to tribal people
*Arcadia (not Arcadia in Greece)
Apart from modern Egypt, it also comprised the former province of Cyrenaica, being the east of modern Libya (an ancient name for the whole African continent as well), split in two provinces, each under a praeses again:
*Libya Superior
*Libya Inferior