A Roman or civil diocese (Latin: dioecēsis, from the Greek: διοίκησις, "administration") was one of the administrative divisions of the later Roman Empire, starting with the Tetrarchy. It formed the intermediate level of government, grouping several provinces and being in turn subordinated to a praetorian prefecture.
The earliest use of "diocese" as an administrative unit was in the Greek-speaking East. Three districts, Cibyra, Apamea, and Synnada, were added to the Province of Cilicia in the time of Cicero, who mentioned the fact in his epistles. The word "diocese" means management district and referred to special which at that time denoted a district pertinent for the collection of taxes, was applied to the territory per se. In the 3rd century the term was applied to temporary judicial districts carved out of proconsular provinces.
Diocletian initiated a reorganization of the imperial administration from the late 280s. He doubled the number of provinces from 47 to almost 100. Smaller and more compact they were easily governable (though the statutory staff complement was only 100. He established mints near heavy concentrations of troops; took censuses; ended arbitrary requisitions as these had become the norm from the 250s for a revised and stable taxation system that gave the Empire a budget in the modern sense for the first time; tried to reestablish a stable coinage; rebuild the army (almost 390,000 + 45,000 in the navy) and infrastructure; centralize justice with the governors; began the removal of their military commands; furthered 'professionalization' the bureaucracy with salaried men of free birth; and in a momentous step taken in the late 280s the creation of regional district 'dioceses' for the Treasury (Res summa) governed by comptrollers (rationales) within which were also housed the regional-level manager (magistri) of Crown Estates (Res Privata). The two ministries worked closely together. The magistri were junior to the comptrollers until the 350s.
For over a century it was the general consenus that the judicial and administrative oversight dioceses governed by vicars were created in 297 as set by Mommsen. However as a result of a 2002 article by Constantin Zuckermann, Travaux et Memoires 14, Melanges Gilbert Dagron, the consensus is growing that the vicariate diocese were created in 313/14, and that the Verona List of June 314 attests to this development. Diocletian did however create a regional set of dioceses for the Treasury (res summa) headed by rationales (fiscal comptrollers). Until the 320s they were involved in most aspects of tax collection with the prefects. Afterwards removed from participation in the collection of taxes in gold and silver due they remained responsible for the actual delivery to their depots or the palace mints and their uses for which they reported to their own superiors and to the officials of the prefecture who composed the budgets of all departments. The SL as the res summa was called from 319 had important duties: the distribution of soldiers' pay in gold and silver; collection of taxes paid by cities, senators and certain classes of business men and women; the operation of start mills; infrastructure and buildings requiring an outlay in gold and silver; the mints; the operation of the mints; mines; clothing for the army, civil service and Courts. The res privata supplied income from rent and taxes and was paid to the emperor. In 366 all rents and taxes paid in kind were commuted to gold and silver payment. Income from it regularly supplemented the imperial budgets. The prefects who were in overall charge of the budget and financial matters: they were responsible for regular in kind taxes, the special in kind tax to support the army (the Annona Militaris) the salaries of all officials under their control, the operation and maintenance of the public post, tax rates. the supply of State armories and mills, most issues pertaining to civil and criminal justice; they were quarter-masters general of the Army; and as a kind of prime minister though not general heads of administration.
The 'fiscal diocese' of the Treasury is the obvious model for the 'vicariate diocese' which was the judicial and administrative oversight counterparts to the fiscal districts though the vicariate it seems were created 25 years after the fiscal. Among the measures taken by Constantine in the years 325-329 one of which was rescinding the right of the SL and RP administrative courts from sending fiscal debt appeals to their superiors at Court: instead these had to go to the prefects, vicars, the urban prefect of Rome and the proconsuls. Thus measure and the abolition of the comptrollers provincial procurators whose duties were shifted to gubernatorial oversight under the watchful eyes of the vicars and comptrollers enhanced the role of the vicars and made them the senior administrators to their Treasury counterparts. These measures were taken to strengthen the already existing financial oversight of the prefects and ensure one locus for budget composition without allowing them to interfere with the day-to-day operation of SL and RP. The emperors were at pains to keep the accounts of these two departments separate from the prefects'. Possibly in the early 340s the monitoring of the regional administration was strengthened by the appointment of senior agentes in rebus, State Investigators as heads of the diocesan office (also in prefectures and two of three proconsular provinces). They were a corps of 2,500 courier/bureaucrats commanded by the master(s) of the offices, minister(s0 of internal security, chiefs of the imperial secretariats, and inspectors-general of the public post. All business in and out of the office was subject to their scrutiny and approval. They were not part of the office staff. They wrote confidential reports to their bosses which the prefects did not see, A. Piganiol, L'Empire chretien (325-395), 1947, p. 321. With 20 years moving about to different parts of the empire and experience seconded to different offices their presence could be a great help to vicars, W. G. Sinnigen, Three Administrative Changes attributed to Constantius II, AJP, 83, 1962, pp. 369-383. Constantine reforms mark a century-long off-and-on struggle between prefects and the heads of the SL and RP for control over the latter, former won for the most part after 430, and which worked in favor of the continuing importance of the vicars, R. Delmaire, Les largesses sacrees et res privata, L'aerarium imperial et son administration du IV au VI siècle, 1989, pp. 703-714; M.F. Hendy, Studies in the Byzantine Monetary Economy, 300-1450 A.D. , 1985.
During the Tetrarchy, each emperor, the Augusti, had a praetorian prefect. The two Caesars did not. Constantine I broke with precedent by appointing Bassus (318) as a third prefect for his son Cripus who had been put in charge of Britain and Gaul in 317. The largest diocese by number of provinces, not area, was the Diocese of the East, which included 16 provinces, while the smallest, the Diocese of Britain, comprised only 4 provinces (Reviews of these developments can be found in the Age of Constantine, Ed. Noel Lenski, Bureaucracy and Government, Christopher Kelly, p. 183-204; David. S Potter, The Empire at Bay, 180-395, pp. 367-377; Cambridge Ancient History, volume XII, pp. 170-183). There were four in 331. A fifth for Africa existed in the tears 335-337. They varied in number from three to four until the number four was fixed in 395: Gaul, Italy, Illyricum and the East, the Illyrican Prefecture existed from 342/43 to 361, and from 375-379 and 388-391. Despite the creation of territorial prefectures the administrative program of the Constantinian Dynasty was diocesan-centered, R. Malcolm Errington, Roman Imperial Policy from Julian to Theodosius, 2006, pp. 80-81, 261-262. The Constantinian prefectures may have more to do with the emperor's dynastic arrangements than administration, T. Barnes, Constantine: Dynasty, , Religion and Power in the Later Roman Empire, 2011, pp. 292-296. These begin to come into their own during the reigns of Constans and Constantius II in the 340s and even more so from the reigns of Valentinian I (364-375 and Valens 364 -378) Joachim Migl, Die Ordnung der Amter, Pratorianer und Vikariat in der Regionsverwaltung des Romishcen Reiches von Konstantin bis zur Valentiischen Dynastie, 1994 and P. Porena, Le origini della prefettura del pretorio tardoantica, 2003; Timothy Barnes, op. cit. Even after the evolution of the prefectures the vicars and dioceses remained important until the 430-440s in particlar as arms of the emperors' centralization and revenue drives from the 350s.
The provinces were grouped into 12 dioceses, each headed by a vicarius i. e. a deputy to a Praefectus praetorio ("Praetorian Prefect"). The Italian diocese had two vicars, one in Rome for the region south of the capital and for the islands and one normally in Milan for northern Italy and the Alpine regions south of the Danube in Bavaria and western Austria. In 321 or by 327 the diocese of Moesia was divided into Dacia and Macedonia. In 370 or 380 Egypt was detached from the diocese of the Oriens (Cilicia, Cyprus, Syria, and Palestine) and made a diocese to establish more direct fiscal accountability and secure the food supply of Constantinople. The dioceses did not and could not have administered the vast territories under their supervision: rather the vicars were a mid-level authority ('Instanz' in German), B. Palme, 'Die Officia der Statthalter in der spatantike,' Antiquite Tardive 7, 1999, pp. 108-110) whose main task was in concert with the SL and RP regional officials the smooth function of the regional admiistration. The vicars absent a prefect or emperor exercised superior authority but with restrictions: they could not change anything decided on at the top level: theirs was to execute, not make policy. Vicars were subordinate to but not under the absolute control of prefects - the vicars shared the authority of prefects; it was not erived to the vicars which gave the latter a measure of autonomy Migl op. cit. pp 54-6 Prefects could not overturn a vicar's verdict unless it was sent on appeal or dismiss them or governors) on their own authority. Provincial governors could still send appeals directly to the Praefectus praetorio who could render a final verdict (vicars could not) or to the Emperor but only after the appeal had first been heard by the vicar in The Theodosian Code 11, 30, 16 (331) which proves the appeal ladder set out by Constantine, John Noel Dillon, The Justice of Constantine, 20 66. p. 248. Their staffs were involved with data collection and processing; judicial matters; and doing much detailed financial work for the prefecture, S. Williams, Diocletian and the Roman Recovery, 1985, p. 110.
The vicars' main tasks were to control and coordinate the activities of provincial governors (actual administration was done at the local level by cities), regulate courts, secure revenue, and monitor the fiscal offices of the Treasury the res summa, renamed in 319 Sacrae Largitiones, i. e., the Imperial treasury which collected monetary taxes and res privata, i. e., the private property of the Emperor. as part of their overall responsibility for the well-being of the regional administration. The vicars' control over governors was direct but not absolute; over the Sl and RP, very limited but focused so as not to be able to interfere with the operation of these two independent ministries but enough require them to report on their legal and fiscal natters (their offices were located in the diocesan see cities except for Corsica, Sardinia and Sicily), namely the authority over fiscal debt cases on appeal and over their staffs in civil and criminal cases and tenants of the RP in major criminal cases. The Vicarii were the principal judicial and financial officials of the regions with general supervision, but restricted power. The main judicial function of the vicars was as to act as appeal judges; as keepers of the regional budget ("the dioceses were the great fisdcal districts of the Empire," CAH XII, p. 181, LoCascio); as monitors of the administration, as regulators of the courts; as coordinators of a highly complex and cumbersome tax collection and distribution system and as guarantors of liturgical assignments issued by governors according to instructions from the prefecture.
Conversion of most tax collection owed the prefectures from in kind to gold and the placement of permanent provincial-level tax collection officials directly under the prefects in the course of the 5th century (instead of sending officials on annual or ad hoc visitations) made the vicars' services increasingly redundant. The diocesan see cities which had been centers of administrative control and major collection hubs for the processing and transmission of information to the prefects; the greater use of direct appeal and the prohibitions that cases of a certain value could had to be dealt with by the lower courts first made the watchdog functions of the vicars redundant increasingly from the 420s. Regarding dioceses as ineffectual and corrupted theEmperor Justinin I abolished the remaining eastern ones in 535 and Egypt in 539 (the southern part of this diocese was from 468 governed by a dux with civil authority, a reversal of the principle established by Diocletian and completed by Constantine I that civil and military spheres be strictly separated unlike before when governors exercised military command, and had judicial and administrative duties (in the 'switch' the fiscal role of the procurators was slowly shifted to governors whose military commands went to a new classes of generals). At the same time he strengthened the authority of provincial governors and increased their pay. This practice was extended to the recovered territory of Africa, where Justinian installed a praetorian prefect and not a vicar (the prefects and a vicar were restored for Italy). In 545 and 548 he restored the dioceses of Pontus and Asia and small Oriens. The vicars there were given vastly increased powers over all other civilian and military officials. For discussions of vicars' judicial powers, Jacek Wiewiorowski, The Judiciary of Diocesan Vicars in the Later Roman Empire, 2016; John Noel Dillon, The Justice of Constantine, 2016; Christopher Kelly, Ruling the Later Roman Empire, 2004 pp. 208-214; A.H.M. Jones, later Roman Empire, 1964, pp.450-462 (financial), 481-486 (judicial), decline of dioceses pp. 280-283; P.S. Barnwell, Emperor, Prefects & Kings, The Roman West, 395-565 for administrative history of the period; for the a critique of the fiscal, L. Edward Alexander Franks, Byzantinishce Zeitscrift, De Gruyter, 2016, Band 109, Heft 2, pp. 987-994.
In the West, the dioceses disappered as Roman power and jurisdiction receded. By 440 only the Italian and Gallic dioceses were still in operation: The vicar in Rome had important tasks to perform for the administration of Peninuslar Italy and the Islands. The Vicar of the Seven Provinces in South Gaul (who also managed the Diocese of Gaul) worked effectively with the praetorian prefect (located from Trier to Arles in 407) to maintain Roman control as much as possible until the very end in 475. In the East, all diocese survived except for Thrace which Anastasius abolished early in his reign (491-518). The dioceses of Oriens and Egypt continued to play important roles post-450 because of tgheir wealth and strategic locations. However the others slipped into morbidity (Jones op. cit, pp. 280-283, Wiewiorowski, op. cit. pp. 299-301).
Introduction of the term in ecclesiastical usage
Between the 4th and 6th centuries, as the older administrative structure began to crumble, the role of the bishops in the western lands of the Empire enabled those lands and their peoples to maintain a semblance of civilization as the authority of Rome vanished. The senatorial aristocracy, especially in the provinces, continued in many places to serve as sources of local authority to complement the authority assumed by the Church. In Late Antiquity, political power often came to be vested in the spiritual offices of the bishops in each region. This transfer of authority from secular officials to ecclesiastical leaders was natural in that, because of the close integration of the secular and ecclesiastical leadership in the Empire, the areas of ecclesiastical administration always coincided with those of the Roman civil administration.
Therefore, as the Catholic and Eastern Orthodox churches began to define their administrative structures, they relied on the older Roman terminology and methods to describe administrative units and hierarchy, which often caused the division between ecclesiastical and secular authority to disappear. In the Eastern Empire, this became fundamental doctrine: see Caesaropapism and State church of the Roman Empire.
A millennium later this process would be somewhat repeated when the Ottoman Empire conquered the Eastern Roman Empire (see Christianity and Judaism in the Ottoman Empire) and the eastern bishops assumed political roles as the Roman civil structure was stripped away. In modern times, many an ancient diocese, though later divided among several dioceses, has preserved the boundaries of a long-vanished Roman administrative division.
- Diocese, the ecclesiastical territory originally corresponding to a civil diocese
- Exarch, equivalent for vicarius, in Ancient Greek terminology
- Marcus Tullius Cicero, EB, 1911.
- Meyendorff 1989.
- Ostrogorsky, George (1956). History of the Byzantine State. Oxford: Basil Blackwell.
- Meyendorff, John (1989). Imperial unity and Christian divisions: The Church 450-680 A.D. The Church in history. 2. Crestwood, NY: St. Vladimir's Seminary Press.