The Dominate or late Roman Empire was the "despotic" later phase of government, following the earlier period known as the "Principate", in the ancient Roman Empire. It may be considered to begin with the beginning of the reign of Diocletian in 284 after the Third Century Crisis of 235–284, and to end with the collapse of the Western Empire in AD 476, or with the reign of Justinian I (527 to 565) or of Heraclius (610 to 641). In the Eastern half of the Empire, and especially from the time of Justinian I, the system of the Dominate evolved into autocratic absolutism.The term is derived from the Latin dominus, which translates in English to lord or master. This form of address—already used by slaves to address their masters—was used for emperors from the Julio-Claudian (first) dynasty on, but inconsistently – Tiberius in particular is said to have reviled it as sycophancy. It became common under Diocletian, who is therefore a logical choice as the first ruler of the "early" dominate, since he dropped the earlier titles of Imperator Caesar for the new ones of Dominus Noster. 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.In contrast to the situation in the Principate however, emperors in the Dominate could not be deified as it was, excepting the two initial decades, the Christian period of the Roman Empire.