Inauguration of the Dominate in Rome

The inauguration of the dominate placed the rule of the Roman Empire on a formally and explicitly authoritarian basis to provide stability in a troubled political climate.

Summary of Event

The Roman Empire has been traditionally divided into two great periods: the principate as founded by Augustus and the dominate as reconstituted by Diocletian. The difference in tone between the two periods is well indicated by their separate names: Principate, derived from princeps, or first man, indicates that the emperor was, at least in theory, a constitutional magistrate. Dominate, on the other hand, taken from dominus, meaning lord or master, acknowledges the fact that the emperor was an absolute ruler. Diocletian

From the assassination of Severus Alexander in 235 c.e. to the accession of the Dalmatian peasant and successful general Diocletian in 284, the Roman Empire had been in a state of almost continuous anarchy. Thanks to assassinations and wars, only one of the more than twenty emperors who ruled during this period had died a natural death. Ruinous taxes, a plague that lasted from 253 to 268, wars with the Persians, and barbarian threats further afflicted the empire.

In the face of these difficulties, Diocletian effected a series of controversial reforms. Changes to make the army more mobile, arrangement for planned retirement of emperors after twenty years and for peaceful successions by trained caesars, and division of the state into four major districts with courts and capitals in Nicomedia, Milan, Trier, and Sirmium were ways in which Diocletian further divided the empire for administrative purposes into twelve dioceses. Each diocese was under a vicar subject to the praetorian prefect of his respective augustus or caesar, and Diocletian enlarged the number of provinces to one hundred. In the new provincial arrangement, military authority was separated from the civil, the former under duces, or “dukes,” the latter under comites, or “counts.” The old haphazard land tax was replaced with a new system based on a division of land into juga of uniform value in each diocese and a similar division of men and animals into units known as capita. At stipulated periods, praetorian prefects had to estimate the budget in terms of goods and make an assessment, or indictio, according to juga and capita.

These reforms, however wise or necessary, were not made without cost. Already during the Severi, the emperorship and the state had been brutalized by falling under military domination. The state had to resort to liturgies to bolster the flagging collection of taxes. Rich men and members of collegia were forced to provide free services and supplies to balance the budget. During the Severi, moreover, Roman jurisprudence divorced both criminal and civil jurisdiction from vestiges of Republican institutions such as the senate of Rome, which under Diocletian became a provincial city. Ulpian’s dictum well presaged the absolutism of Diocletian in asserting that the “will of the prince has the force of law.” It was becoming more and more obvious that citizens were existing for the benefit of the state rather than the other way around.

Diocletian’s reign can readily be seen as representative of this trend toward totalitarian control. The cost of supporting four elaborate courts and the enlarged army added to the burden of the already impoverished economy. Inadequate issuance of new gold and silver coins and overdevaluation of others encouraged rapid inflation. Consequently in 301 c.e., Diocletian attempted to control the economy by issuing his famous Edict of Prices, fixing the maximum that could be paid for all kinds of goods and services. Despite severe penalties, the law proved to be unworkable and eventually had to be permitted to lapse. To prevent people from avoiding the more thorough collection of taxes, farmers became bound to their land and workmen to their trades. Moreover, sons had to take up the same labors as their fathers, thereby creating a kind of serfdom in the country and a caste system in the cities.


Historians have often tended to overemphasize the rigidity of Diocletian’s regime. Whether because of a misleading comparison with twentieth century socialism or a dislike of Diocletian’s persecution of the Christians, historians have underestimated the significance of Diocletian’s constitutional reforms. These reforms proceeded from a genuine vision of how the Roman Empire could be reconstituted and once again be made a formidable and cohesive force.

Particularly important was the mechanism Diocletian devised for the imperial succession. Typically, the reigning emperor had been suspicious of any particularly strong man among those who served him; this suspicion led either to the elimination of the rivals or their preemptive overthrow of the emperor. By granting ambitious, energetic men a junior share in government and promising them eventual leadership, Diocletian defused the air of suspicion and intrigue that had plagued Roman statesmanship for several decades. Although his system ultimately collapsed, it still provided the Roman Empire with twenty years of good government, and the imperial succession would never again be so unstable as it had been in the third century.

Also notable (and rare in Roman imperial history) was Diocletian’s willingness to abdicate the throne after serving his twenty years. This action, which hearkened back to the old Roman virtues of rectitude and patriotic self-sacrifice and was only reluctantly emulated by Maximian, indicates that Diocletian adhered to his own standards of conduct and was not merely an opportunistic dictator. Diocletian’s authoritarianism, unlike so many others, possessed a rationale and a logic.

Indicative of the new atmosphere, Diocletian introduced an elaborate ceremonial protocol into his court borrowed from Persian and earlier Hellenistic rulers. On formal occasions, he wore a robe of purple silk and shoes adorned with jewels and was seated on a throne. He insisted upon being styled dominus, or lord, and those admitted to his presence had to perform the proskynesis, or prostration, to kiss the hem of his robe. Many historians profess to see in the declining art of the period the trend toward domination by the emperor.

Finally, although not as an innovator, Diocletian took control over the consciences of his subjects. Diocletian believed in using the prestige of the classical gods to buttress his own power; thus he allowed himself to be described as “Jove” and Maximian as “Hercules.” A conservative polytheist convinced that the prosperity of the state depended on the favor of the gods, Diocletian issued decrees against Manichaeans in 297 c.e. and instituted the great persecution against the Christians in 303-304. This dragnet, which required all to display a certificate of sacrifice to the gods, came to a permanent end only with the Edict of Milan in 313 and the so-called Peace of the Church.

Further Reading

  • Barnes, Timothy. The New Empire of Diocletian and Constantine. Cambridge, Mass.: Harvard University Press, 1982. A compendium of laws and records make this source useful for research on Diocletian.
  • Cameron, Averil. The Later Roman Empire a.d. 284-430. London: Fontana, 1993. Cameron provides a crisply written and cogent analysis of the period.
  • Corcoran, Simon. The Empire of the Tetrarchs: Imperial Pronouncements and Government, a.d. 284-324. Oxford, England: Clarendon Press, 1996. Explores the legal and political basis of the Dominate.
  • Jones, A. H. M. The Later Roman Empire, 284-602. Baltimore: The Johns Hopkins University Press, 1986. Describes Diocletian’s impact on the entire period of late antiquity.
  • Southern, Pat. The Roman Empire from Severus to Constantine. New York: Routledge, 2001. A look at the Roman Empire from the viewpoint of its rulers. Covers Diocletian.
  • Victor, Sextus Aurelius. Liber de Caesaribus of Sextus Aurelius Victor. Translated with an introduction and commentary by H. W. Bird. Liverpool, England: Liverpool University Press, 1994. Bird has provided a fine translation of the main primary source for Diocletian, accompanied by an excellent, modern-day commentary.
  • Williams, Stephen. Diocletian and the Roman Recovery. London: B. T. Batsford, 1985. This source is particularly recommended as the most thorough analysis available of Diocletian and his time.

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