Vicarius is a Latin word, meaning substitute or deputy. It is the root of the English word "vicar." In the broadest sense, a vicar (from the Latin vicarius) is anyone acting as a substitute or agent for a superior (compare vicarious). In this sense, the title is comparable to lieutenant. ...

In ancient Rome, this was the partial title for various officials. Each vicarius was assigned to another superior official, after whom his full title was generally completed. (e.g. Vicarius Praetor) However, there was an exception to this usage in which both the title and position were singular, simply referred to as a vicarius.

During the later period of the Roman Empire known as the "Dominate" or "Tetrarchy", a vicarius was the imperial deputy in charge of a group of Roman provinces called a diocese. This position was introduced under Emperor Diocletian who reformed the Roman Empire, collegially, into the Tetrarchy. Under this system, the empire was ruled by two Augusti (senior emperors) and each was assisted by a Caesar (junior emperor) who acted as a deputy and was groomed to become the next 'Augustus'. Thus a Tetrarchy was a rule by four individuals. (These deputies were soon abolished as a regular institution - leaving only two emperors.) The eastern and western empires were each divided into two large praetorian prefectures. The Roman Kingdom (Latin: Regenum Romanum) was the monarchal government for the city of Rome and its territories from its founding in 753 BC by Romulus until the expulsion of Lucius Tarquinius Superbus in 510 BC and the establishment of the Roman Republic. ... Jump to: navigation, search See also Roman Republic (18th century) and Roman Republic (19th century). ... Jump to: navigation, search The Roman Empire is the term conventionally used to describe the Ancient Roman polity in the centuries following its reorganization under the leadership of Octavian (better known as Caesar Augustus). ... The Principate is, according to its etymological derivation from the Latin word princeps, meaning chief or first, the political regime dominated by such a head of state and government. ... The Dominate was the despotic last of the two phases of government in the ancient Roman Empire between its establishment in 27 BC and the formal date of the collapse of the Western Empire in AD 476. ... Jump to: navigation, search The Western Roman Empire is the name given to the western half of the Roman Empire after its division by Diocletian in 286 AD. It would exist intermittently in several periods between the 3rd Century and the 5th Century, after Diocletians Tetrarchy and the reunifications... Jump to: navigation, search The Byzantine Empire is the term conventionally used to describe the Greek-speaking Roman Empire during the Middle Ages, centred at its capital in Constantinople. ... Magistratus ordinarii (ordinary magistrates) and Magistrarus extraordinarii (extraordinary magistrates) were two categories of officials who held political, military, and, in some cases, religious power in the Roman Republic. ... For modern diplomatic consuls, see Consulate general. ... Jump to: navigation, search // Definition According to Cicero, Praetor was a title which designated the consuls as the leaders of the armies of the state. ... Quaestors were elected officials of the Roman Republic who supervised the treasury and financial affairs of the state, its armies and its officers. ... See Roman Governor for the duties of a promagistrate as a governor of a province A promagistrate is a person who acts in and with the authority and capacity of a magistrate, but without holding a magisterial office. ... Aedile (Latin Aedilis) was an office of the Roman Republic. ... Jump to: navigation, search Tribune (from the Latin: tribunus; Greek form tribounos) was a title shared by several elected magistracies and other governmental and/or (para)military offices of the Roman Republic and Empire. ... Jump to: navigation, search For omission and secrecy, see censorship. ... A Roman governor was an official either elected or appointed to be the chief adminstator of Roman law throughout one or more of Ancient Romes many provinces. ... Magistratus ordinarii (ordinary magistrates) and Magistrarus extraordinarii (extraordinary magistrates) were two categories of officials who held political, military, and, in some cases, religious power in the Roman Republic. ... Dictator was a political office of the Roman Republic. ... Jump to: navigation, search The Master of the Horse was (and in some cases, is) a historical position of varying importance in several European nations. ... Jump to: navigation, search The term triumvirate (Latin for rule by three men) or troika in Russian, is commonly used to describe an alliance between three equally powerful political or military leaders. ... Decemviri (sing. ... Jump to: navigation, search Alternate meanings: see Pontifex (disambiguation) In Ancient Rome, the Pontifex Maximus was the high priest of the collegium of the Pontifices, the most august position in Roman religion, open only to a patrician, until 254 BC, when a plebian occupied this post. ... A legatus (often anglicized as legate) was equivalent to a modern general officer in the Roman army. ... Dux is Latin for leader (from the verb ducere, to pull) and could refer to anyone who commanded two or more legions. ... Officium (plural officia) is a Latin word with various meanings, including service, (sense of) duty, courtesy, ceremony and the likes. ... A prefect (from the Latin praefectus, perfect participle of praeficio, to make in front, i. ... The Vigintisexviri (sing. ... Magister militum (Master of the Soldiers) was a rank used in the later Roman Empire dating from the reign of Constantine. ... The Latin word imperator was a title originally roughly equivalent to commander during the period of the Roman Republic. ... The princeps senatus (plural principes senatus) was the leader of the Roman senate. ... Jump to: navigation, search Roman Emperor is the title historians use to refer to rulers of the Roman Empire, after the epoch conventionally named the Roman Republic. ... Augustus (plural augusti) is Latin for majestic or venerable. The feminine form is Augusta. ... Caesar (p. ... The Tetrarchs, a porphyry sculpture sacked from a Byzantine palace in 1204, Treasury of St. ... Jump to: navigation, search This is a tentative list of topics regarding political institutions of Ancient Rome. ... Jump to: navigation, search The Roman Republic (Latin: Res Publica Romanorum) vested formal governmental powers in four separate peoples assemblies — the Comitia Curiata, the Comitia Centuriata, the Comitia Tributa, and the Concilium Plebis. ... The Roman Senate (Latin, Senatus) was a deliberative body which was important in the government of both the Roman Republic and the Roman Empire. ... Jump to: navigation, search Imperium can, in a broad sense, be translated as power. ... Jump to: navigation, search Roman Law is the legal system of ancient Rome. ... The cursus honorum (Latin: succession of magistracies) was the sequential order of public offices held by aspiring politicians in both the Roman Republic and the early Empire. ... Collegiality is the relationship between colleagues. ... Jump to: navigation, search The Roman Empire is the term conventionally used to describe the Ancient Roman polity in the centuries following its reorganization under the leadership of Octavian (better known as Caesar Augustus). ... The Dominate was the despotic last of the two phases of government in the ancient Roman Empire between its establishment in 27 BC and the formal date of the collapse of the Western Empire in AD 476. ... The Tetrarchs, a porphyry sculpture sacked from a Byzantine palace in 1204, Treasury of St. ... Jump to: navigation, search Map of the Roman Empire, with the provinces, after 120 AD. In Ancient Rome, a province (Latin, provincia, pl. ... Jump to: navigation, search Pope Pius XI blesses Bishop Stephen Alencastre as fifth Apostolic Vicar of the Hawaiian Islands in a Cathedral of Our Lady of Peace window. ... Jump to: navigation, search Emperor Diocletian Gaius Aurelius Valerius Diocletianus (245?-312? AD), born Diocles, was Roman Emperor from November 20, 284 to May 1, 305. ... A senior Greek emperor. ... Caesar (p. ... The division of the Roman Empire into four Praetorian prefectures originated in the age of the Tetrarchy yet outlived that period. ...

Each of the four prefectures was run by a Praetorian Prefect (originally the 'chief of staff' of each of the four imperial tetrarchs) and contained several dioceses and the vicarius of each diocese was responsible for a number of provinces, each province with its own governor. Praetorian prefect (Latin Praefectus praetorio) was the constant title of a high office in the Roman state that changed fundamentally in nature. ... A tetrarch is a Greek term that strictly identifies one of four governors of a divided province. ... Jump to: navigation, search A governor is also a device that regulates the speed of a machine. ...

For example, the western empire was divided into Italia (Italy & Africa) and Galliae (the Gauls). Galliae contained the four dioceses of Britain, Hispania, Viennensis and Gaul. The diocese of Britain was divided into four (and later five) provinces and the vicarius of Britain, based in London, oversaw the governors of each of the British provinces. Jump to: navigation, search Roman aqueduct in Segovia Hispania was the name given by the Romans to the whole of the Iberian Peninsula (modern Portugal, Spain, Andorra and Gibraltar) and to two provinces created there in the period of the Roman Republic: Hispania Citerior and Hispania Ulterior. ... Map of Gaul circa 58 BC Gaul (from Latin Gallia, c. ... London is the capital city of the United Kingdom and of England. ...

The various prefectures, dioceses and provinces are listed systematically in their hierarchical groupings in the article Roman province. Jump to: navigation, search Map of the Roman Empire, with the provinces, after 120 AD. In Ancient Rome, a province (Latin, provincia, pl. ...