A Roman or civil diocese ("Latin: dioecēsis, from "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 word 'diocese' means 'management district.' It referred to a district for the collection of taxes and was applied to the territory per se. 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. In the 3rd century A.D. the word was applied to temporary districts carved within a proconsular provinces, governance of which was assigned to officials called correctors on staff, CAH XII, p. 161. From time to time some provinces were governed by extraordinary official called vicarii from the equestrian order instead of proconsuls, ibid. However these are not to be considered the antecedents of the later vicariate dioceses.
Regional fiscal districts named dioceses appear early in the reign of Diocletian. The are possibly the models for the vicariate dioceses headed by vicars of prefects appear either at the very end of the 3rd century or early in the 4th. It was thought that the creation of dioceses and permanent vicars were components of a cluster of measures taken in the years 293-297 to overhaul the administration and fiscal machinery of the empire and rebuild the army. For over a century the 'general consensus' was the these had been created in 297 to supervise the division of provinces and hasten the pace of fiscal reforms whose signature feature was a massive set of censuses that started in 287 and took fifteen years to complete: the results were used as the bases for the introduction of a new tax computation system that gave the empire for the first time regular budget in a modern sense. The scholarly world has debated whether Diocletian's program was undertaken "by a cautious government working steadily towards its intended goals; or perhaps"..."a rather arbitrary series of akeshift reactions," Roger Rees, Diocletian and the Tetrarchy, 2004, p. 39. However, if the permanent dioceses were created in 313/14 (discussed below) the motive for their creation would have been control of regions since the tasks which they supposed to have been undertaken earlier were already completed.
As part of his renovation of the empire Diocletian established mints near heavy concentrations of troops; Starting in the early 290s Diocletian ordered the division of the 47 provinces. By the of his reign in 305 they were 100 or just over. He ended arbitrary army requisitions (plundering) which had become almost norm from the 250s and replaced it with a revised, stable taxation and delivery system; tried to recreate a stable coinage; rebuild the army (in 285 A.D. 390,000 + 46,000 in round numbers according to John Lydus a 6th century bureaucrat of the prefecture of the East - numbers vary from 400-000 - 600,000 for the 4th century); instituted much needed infrastructure repairs after years of neglect; centralized the administration of justice with governors; began the removal of their military commands (which Constantine completed in 313-314 by removing the last remaining military commands from governors who still had them and from the prefects); made liturgies (free services either monetarily, in labor and supplies) obligatory; furthered 'professionalization' the bureaucracy with salaried men of free birth; and instituted an interventionist policy towards local government and allocating their fiscal obligations drawn up in detail at the highest level rather than allowing the city councils to allocate the tax demands as they saw fit which caused considerable resentment among the heretofore autonomous city-states that were the model administrative units and backbone of the empire. The doubled number of provinces were smaller and more compact and, therefore, more easily governable (though the statutory staff complement was only 100). They had to be since the governors who were mainly judicial and administrative officials were given more financial responsibilities as the old system of treasury procurators was slowly phased out.
The creation of the regional districts or 'dioceses' for the Treasury (Res Summa) governed by comptrollers (rationales) within which were also housed the regional-level managers (magistri) of the Crown Estates (Res Privata) using the already extant unitary fiscal district of Egypt, which at the time included Cyrenaica and Crete (detached in 294 united with Achaia). The 'new' Egyptian unit appears in 286 (same tasks but a new title for the comptroller). Some of the other districts are attested to subsequently in what looks like a empire-wide development. This 'fiscal diocese' of the Treasury is the obvious model for the 'vicariate diocese.' These two ministries at the regional level worked closely together with the diocesan vicars as a kind of regional administrative triumvirate; and their rise and demise is linked together though not fully-synchronic. The magistri were junior to the comptrollers until the 350s but the close connection was maintained as bitted two departments of government from which the emperor derived the greatest amount of gold and silver revenues during the 4th century (in the West much of the Res Privata income went to the Res Summa (called the Saecrae Largitiones from 319). Before 366 RP taxes could be paid in kind or in gold and silver; afterwards in specie only as part of a revenue drive. The SL was responsible for the distribution of soldiers' gold and silver emoluments; the collection of taxes paid by cities, senators and certain classes of business men and women; the operation of clothing mills; funds for infrastructure and buildings which required an outlay in gold or silver; the operation of the mints and mines; clothing supply to the army, Civil Service and Imperial Courts. The Res Privata supplied income to the emperors from rent and taxes paid on leased lands to private individuals (most of it) or managed directly by imperial officials.
The praetorian prefects were the superiors of the vicars. The 'canonical' number was two which Diocletian maintained even during the Tetrarchy 293-305. 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. There were no formal territorial prefectures until 330. It was not until the early 340s that the prefectures take on something of an administrative role which emergence more prominently from the late 360s. 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. The number was fixed at four in 395. 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 particular as arms of the emperors' centralization and revenue drives from the mid-360s, and as agents of the prefects' encroachments on the independence of SP and RP which resisted through the 440s.
The prefects were the chief judicial, administrative and financial officials of the empire, imperial vice-regents, quarter-masters generals of the army and in overall charge of the budgets (composed regionally, i.e. by diocese): they were responsible for 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, and the construction and repair of roads, harbors and state granaries; the supply of State armories and mills, and most issues pertaining to civil and criminal justice not assigned to the administrative courts of the Sl and RP and the military. They acted as 'prime ministers' though not general heads of administration, the oversight of which they had to share with the masters of the offices increasingly from the 320s. From 325-326 they assumed control over the regular land tax revenue collection and delivery after Constantine removed any participation in their collection from the SL. The emperor also assigned them maintenance and operation of the State Post and Freight Service (inspection and use of which from the early 340s was placed under the Masters of the Offices who were the Ministers of State Security, Internal Affairs and Heads of the Imperial Secretariates through which business from all departments was normally channeled to the emperors - another of many overlaps). Prefects were not supposed to interfere with the normal, routine operations of the SL and RP. The vicars and governors monitored the activity of SL staff on provincial assignment who were supposed to work with and through the governors in matters pertaining the SL taxes. In doing so they were to have have nothing to do with the provincials because of their reputation for corruption and extortion.
Initially there were 12 dioceses for 100+ provinces, 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 administration. 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, pp.1 83-204; David. S Potter, The Empire at Bay, 180-395, pp.367–377; Cambridge Ancient History, volume XII, pp.170–183). 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 new vicars from the beginning were mainly judicial counterparts to the regional comptrollers and managers of the SL and RP - their duties overlapped in discrete ways deliberately it seems to create mutual checks on each other, force joint accountability and "ensure that senior office holders might police the actions of their colleagues," The Cambridge Companion to the Age of Constantine, Ed. Noel Lenski, 'Law and Society,' Christopher Kelly, p. 191 - a main function of vicars was oversight and in particular acting as 'fiscal cops' within the diocese. L. Edward Alexander Franks, Byzantinishce Zeitscrift, De Gruyter, 2016, Band 109, Heft 2, pp. 991. Although subordinate to the prefects from the very beginning of their existence the vicars (and the counts of provinces introduced in 316 and terminated in 340) "The degree of subordination of these officials to the Praetorian Prefects, at least in some judicial matters. is also uncertain," Kelly op. cit. p. 185. Greater prefectural control may have been achieved towards the end of the 4th century when they were allowed to dismiss vicars pending imperial approval. Prefects could not overturn a vicar's verdict unless it was sent on appeal or dismiss them on their own authority. The vicars absent a prefect or emperor were at the apex of the civilian administration and exercised their superior authority but with restrictions: they could not change anything decided on at the top level: theirs was to execute, not make policy. Whether vicars shared the prefects' authority, Migl op. cit. pp 54–6. Provincial governors could still send appeals directly to the "Praefectus praetorio who could render a final verdict or to an emperor, but only after the appeal had first been heard by the vicar as seen a law of the Theodosian Code 11, 30, 16 (331) which supports the double appeal route set out by Constantine, John Noel Dillon, The Justice of Constantine, 20 66. p. 248.
Though of the same rank as the comptrollers and managers, all equestrian perfectissimi, the authority of the vicar was superior (appellate) to that of the other two who only had first instance jurisdiction (like governors). Vicars also had first instance authority to facilitate their roles as regulators of the courts by intervening in lower courts to prevent irregularities and corruption - they were supposed to use sparingly and not to actually take cases from the provincial courts unless for good cause. However, litigants tried to have vicars take their cases from the lower courts in order to shorten to get a more definitive verdict immediately or shorten the time and expense of appeal process. In 326 vicars were raised to senatorial status. In addition to their judicial roles the vicars also were the regional civilian quarter-masters general of the army(a measure undertaken by Diocletian to remove army logistics and supply matters from the military in order to get a strange hold on it by using civilian administration); and they exercised some general oversight of the diocese without being the administrators: administration was primarily carried out at the provincial and municipal levels. The diocesan 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 (they could not appoint or dismiss them, but could investigate them and fine them); over the Sl and RP, the vicars had very limited but focused authority so as not to be able to interfere with the normal routine 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, Sicily and one of the Pannonian provinces). The vicars had appeal authority in fiscal debt cases, and jurisdiction over their staffs in civil and criminal cases and over tenants of the RP in major criminal cases. 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 fiscal districts of the Empire," CAH XII, p.181, LoCascio); monitors of the administration, regulators of the courts; and as coordinators of a highly complex and cumbersome tax collection and distribution systems; guarantors of liturgical assignments issued by governors according to instructions from the prefecture; and as the civilian quartermaster-generals of the army. In 385 the counts of the SL and RP at Court were once again allowed to take appeals form the rationales and procurators (of the RP) in their respective departments in a move to possibly streamline and expedite these cases at a time of imperial financial duress: the restoration is possibly the first major change in the role the vicars who nonetheless could receive appeals as before. Until then the trajectory of additional responsibilities had been upwards.
Until the 320s the regional heads of the SL were involved in most aspects of tax collection under their respective heads at the highest palatine level with the emperors. The vicars' role was general oversight. Constantine put vicars clearly in charge. In the years 325-330 the SL rationales were removed from the actual participation in the collection of most taxes in gold and silver (and in kind such as military uniforms) due their offices (this task had been placed with the governors). They remained responsible for oversight of the collections and for the actual delivery to their depots or the palace mints and continued to have supervisory authority to make sure income due them was not diverted to the prefecture. The emperor also re-directed appeals of the rationales decisions in fiscal debt cases re their revenue stream to the vicars, prefects and proconsuls thereby giving them a measure of control over these the two fiscal departments. They also had jurisdiction over the staffs their staffs in civil and criminal suits (the SL was given control in civil suits in 385) - they would be tried in the provincial, not administrative courts. The vicars at the administrative apex of the dioceses, worked closely with their regional counterparts who has slipped into junior position, Franks op. cit.
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 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.
The conversion of most of the prefectures' taxes from in kind collection to payment gold began very slowly under Constantine I; and, in any case, was was resorted to in certain circumstances (if it were more convenient to buy supplies locally rather than having to collect and transport these from a distance and proximity to military units). By the end of the 4th and beginning of the 5th century the pace of conversion to collection of taxes in gold had quickened especially in the West. The process of commutation to gold was completed mostly in the West by 425 and in the East by the last decades of the century (though collection in kind never ceased and was resorted to as needed in the form of requisitions). The placement of permanent provincial-level tax collection officials directly under the prefects in the course of the 5th century (instead of relying on officials sent on annual or ad hoc visitations from central headquarters) made the vicars' services and dioceses increasingly redundant. Also the greater use of direct appeal and the regulations that cases under a certain value threshold be dealt with by the vicars' courts while the most important cases be sent to the highest echelon marginalized their courts though the vicars' watchdog fiscal role continued for the rest of the 5th century in the East as seen in CJ 10, 13, 4 (468) which instructs them to make sure that the revenues of the SL were not reallocated to the prefecture by the governors and the prefects' agents.
The process of diocesan rise and decline was very slow: upward trajectory in strictly regulatory matters until 385 but in practice until the early fifth century followed by a plateau and then decline post 440.The Constantinian Dynasty favored "a regionally-based centralism, and on the other, the gradual separation of the regions," R. Malcom Errington, Roman Imperial Policy from Julian to Theodosius, 2006, pp. 261-262. This policy was slowly abandoned post-363 in favor of greater central control the empire faced serious challenges financially and from invasions. In 372 Valentinian I raised vicars to the second rank of senators of spectabilis: they were to rise no higher. The vicars, however, continued to play a very important role as they were enlisted in the imperial effort to meet revenue demands and maintain the stability and effectiveness of the administrative system. Indeed the sum total of source material in the Theodosian Code published in 438 suggests the compilers thought dioceses were still running on 7 if not 8 cylinders (their functioning is somewhat difficult to detect as they are subsumed by the prefectures especially after these come to the fore). However, the vicars and dioceses slipped into steeper decline after 450 A.D., as did their regional counterparts of the SL and RP. Theirs court were more and more bypassed and their financial responsibilities atrophied, Jones op. cit. pp. 280-283. 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 control as much as possible and wherever it existed until the very end of Roman rule in 475. The vicar in Rome continued to perform important functions for the city of Rome, southern Italy and the Islands on behalf of the prefect in Ravenna. However, with the exception of Oriens and Egypt because of their strategic locations and wealth, the Balkan and Anatolian dioceses slipped into morbidity, Jones ibid.; Wiewiorowski, op. cit. pp. 74, 299–301; Delmaire, op. cit, pp. 703-714.
Regarding dioceses as ineffectual and corrupted the "Emperor Justinian I abolished the remaining ones in the East (Thrace disappeared early in the reign of Anastasius I 491-519: Asia, Pontus, Dacia and Macedonia were abolished 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. the remnants of the intermediate tier finally withered away in the early 7th century. A truncated Eastern Roman Empire from 637 A.D. had no need for it - direct central control through provinces and then Themes was the order of the day. 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 a critique of the fiscal, L. Edward Alexander Franks, Byzantinishce Zeitscrift, De Gruyter, 2016, Band 109, Heft 2, pp.987–994.
The diocesan see cities for over 125 years had been centers of regional administrative control and oversight. They were major collection hubs for processing and transmission of information to the palatine level from governors, the regional and provincial agents of the Treasury and Crown Estates, and municipalities. Changed conditions in the 5th century - the drift towards a two rather than three-tier imperial administration, commutation of taxes, and direct appeals - resulted in dioceses taking back seat rather than central stage.
From the beginning the Romans ran their empire 'on the cheap.' Officials were few. Unpaid locals did their work for them, "The close binding of the civic governing structures to the empire made it possible to avoid a distributed permanent professional civil service in individual cities," Roger S. Bagnall, Egypt in Late Antiquity, 1993, p. 62 (and quoting Bowman, 'The Town Councils of Roman Egypt' (Am.Stud.Pap. 1, Toronto who says this "policy of amateurism was a failure, in the sense that it combined ineffectiveness and oppression"). It was also dangerous because the richer who were responsible for administration were taxpayers, a conflict of interest. The 4th century saw an improvement in the imperial bureaucracy and a great expansion from 10,000 to 30-40,000: it was more professional, free-born, salaried, and pensioned. "Despite its many manifest failings the civil services undoubtedly played a vital part in the preservation of the empire,' Jones, LRE p. 606. They knew procedure and regulations, ibid. The diocese was part of this evolution. However with only 300 stipendiary staff (600 in Oriens and 400 in Africa) the existence of the diocese did not change the philosophy of governance which was having the locals (i.e. city states) do the work. The diocese's purpose, rather, was to control the imperial administrative machinery at the provincial level by leaning on governors to get more performance results and through them from the cities and other local units. The appointment of permanent officials from central office in provinces and the placement of imperial officials in cities as solutions to the problem of control happened post-450(?): this undercut a major reason for the diocesan level by bypassing it.
It has been said the history of Roman is the history of a State. The dioceses were on-the-spot extensions of the Roman state. After regions were lost provincial and municipal administration under new rulers continued more or less as before in most areas: however, the imperial supra-structure that in a very real was the Roman State during the Later Roman Empire was gone.
In the 5th and 6th centuries, as the older administrative structure began to crumble in the West, the role of the bishops in these regions 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 often coincided with those of the Roman civil administration form which they had derived; 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.