Origin

Origin

• The Tetrarchy
  

During the 3rd century, three crises threatened the Roman Empire: external invasions, internal civil wars and an economy riddled with weaknesses and problems.The city of Rome gradually became less important as an administrative centre. The crisis of the 3rd century displayed the defects of the heterogeneous system of government that Augustus had established to administer his immense dominion. His successors had introduced some modifications, but events made it clearer that a new, more centralised and more uniform system was required.Diocletian was responsible for creating a new administrative system (the tetrarchy).He associated himself with a co-emperor, or Augustus. Each Augustus was then to adopt a young colleague, or Caesar, to share in the rule and eventually to succeed the senior partner. After the abdication of Diocletian and Maximian, however, the tetrachy collapsed, and Constantine I replaced it with the dynastic principle of hereditary succession.

• Constantine I and his successors
  

Constantine moved the seat of the Empire, and introduced important changes into its civil and religious constitution. In 330, he founded Constantinople as a second Rome on the site of Byzantium, which was well-positioned astride the trade routes between East and West; it was a superb base from which to guard the Danube river, and was reasonably close to the Eastern frontiers. Constantine also began the building of the great fortifide walls, which were expanded and rebuilt in subsequent ages. J.B bury asserts that "the foundation of Constantinople inaugurated a permanent division between the Eastern and Western, the Greek and the Latin, halves of the Empire—a division to which events had already pointed—and affected decisively the whole subsequent history of Europe.Constantine built upon the administrative reforms introduced by Diocletian.He stabilized the coinage (the gold solidus that he introduced became a highly prized and stable currency), and made changes to the structure of the army. To divide administrative responsibilities, Constantine replaced the single praetorian prefect, who had traditionally exercised both military and civil functions, with regional prefects enjoying civil authority alone. In the course of the 4th century, four great sections emerged from these Constantinian beginnings, and the practice of separating civil from military authority persisted until the 7th century.Under Constantine, Christianity did not become the exclusive religion of the state, but enjoyed imperial preference, since the Emperor supported it with generous privileges: clerics were exempted from personal services and taxation, Christians were preferred for administrative posts, and bishops were entrusted with judicial responsibilities.Constantine established the principle that emperors should not settle questions of doctrine, but should summon general ecclesiastical councils for that purpose. The Synod of Arles was convened by Constantine, and the First Council of Nicaea showcased his claim to be head of the Church.The state of the empire in 395 may be described in terms of the outcome of Constantine's work. The dynastic principle was established so firmly that the emperor who died in that year, Theodosius I, could bequeath the imperial office jointly to his sons: Arcadius in the East and Honorius in the West. Theodosius was the last emperor to rule over the full extent of the empire in both its halves