Such was the Hierarchy, such the Government of the Church, during the Three first Centuries. But in the Fourth and following Ages great Alterations were made in both, the Church adapting her Government to that of the State, namely, to the new Form of Government introduced by _Constantine_, who had settled her in Peace, and taken the Priesthood into his immediate Protection. For it was in his Reign that the Titles of _Patriarchs_, _Exarchs_, _Metropolitans_, were first heard of, or at least had any Power, Authority, or Privileges, annexed to them. That this Conformity between the Civil and Ecclesiastical Polity may appear more plainly, I shall premise a succinct Account of the former, as established by _Constantine_ throughout the Empire. That Prince divided the whole _Roman_ World into four Prefectures, _viz._ the _East_, _Illyricum_, _Gaul_, and _Italy_, which were governed by four Prefects, called _Præfecti Prætorio_. [Sidenote: _The new Form of Government introduced by_ Constantine.] Till his Time the whole Empire was governed under the Emperors by Two Prefects only, as _Zosimus_ informs us[628]; and this Division is supposed to have been made by _Constantine_, jealous of the too great Power of those Magistrates. Each Prefecture was subdivided into several Dioceses, and each Diocese into several Provinces. Thus the Prefecture of the _East_ contained Five Dioceses; _viz._ the _East_ divided into Ten Provinces, _Egypt_ into Six, _Pontus_ into Eleven, _Asia_ into Ten, and _Thrace_ into Six. Under the Prefecture of _Illyricum_ were Two Dioceses; _Macedon_, consisting of Eight Provinces; and _Dacia_, consisting of four. The Prefecture of _Gaul_ comprised Three Dioceses, _Gaul_ made up of Seventeen Provinces, _Spain_ of Seven, and _Britain_ of Five. The Prefecture of _Italy_ was divided into Two Vicarages or Lieutenancies; the one of _Rome_, comprehending Ten Provinces, under the Vicar of _Rome_, whence they were called _Suburbicarian_ Provinces; the other of _Italy_, containing Seven Provinces, governed by the Vicar of _Italy_, who resided at _Milan_, whence they were simply called Provinces of _Italy_. Under the Prefect of _Italy_ was likewise _West Africa_, and after _Constantine_’s Death _West Illyricum_. The Prefects had other Officers under them, by whom the Provinces were more immediately governed. These were, to name them according to their Rank and Dignity, Proconsuls, Vicars, Consulars, Correctors, and Presidents. Each Diocese had its Metropolis, and likewise each Province contained in the Diocese. [Sidenote: _The Civil and Ecclesiastical Polity compared._]