Dominate

The Dominate was the 'despotic' latter phase of government in the ancient Roman Empire from the conclusion of the Third Century Crisis of 235–284 until the formal date of the collapse of the Western Empire in AD 476. It followed the period known as the Principate. In the Eastern half of the Empire, and especially from the time of Justinian I, the system of the Dominate evolved into Byzantine absolutism.

The word is derived from the Latin dominus, meaning lord or master, as an owner versus his slave — this had been used sycophantically to address emperors from the Julio-Claudian (first) dynasty on, but not used by them as a style — Tiberius in particular is said to have reviled it openly. It became common under Diocletian, who is therefore a logical choice as the first ruler of the 'early' dominate. Historian David Potter describes the transformation of Government under Diocletian when describing the shifts in imagery the Emperor used to display his power (in this case the building of a huge new palace at Sirmium):

The style of Government so memorably described by Marcus, whereby the emperor sought to show himself as a model of correct aristocratic deportment, had given way to a style in which the emperor was seen to be distinct from all other mortals. His house could no longer be a grander version of houses that other people might live in: it, like him, had to be different.

The first phase of Imperial government, known as the Principate, when the formalities of the constitutionally-never-abolished republic were still very much the 'politically correct' image, has also often been said to have ended after the Third Century Crisis of 235–284, which concluded when Diocletian established himself as Emperor. Moving the notion of the Emperor away from the republican forms of the Empire's first three centuries, Diocletian introduced a novel system of joint rule by four, the tetrarchy, and he and his colleagues and his successors (in two imperial territories, east and west, not four) chose to stop using the title princeps, instead openly displaying the naked face of Imperial power and adopting a Hellenistic style of government more influenced by the veneration of the Eastern potentates of ancient Egypt and Persia than by the heritage of civic collegiality amongst the governing class passed down from the days of the 'uncrowned' Roman Republic.

Arguably, more crucial than the chosen title was the earlier adoption of a divine status as divus, originally a posthumous exceptional honour awarded by the senate, later granted to the living emperor (and some members of his dynasty), becoming an unwritten prerogative of the crown.

Another clear symptom of the upgrading of the imperial status was that he came to incarnate the notion (abstract under the uncrowned republic) of the majesty of Rome, so that lese majeste became high treason.

Contemporary historians reject the interpretation of the transition from Principate to Dominate as a clear, easily definable break (cf. Late Antiquity). Rather, they now characterise it as a much more subtle, gradual transformation, in which Diocletian's reforms of the Imperial office, while significant, are but one point on a sliding scale. Nevertheless, the distinction between two primary phases of Imperial government in Rome remains an important and useful one.