diocese(redirected from Arch-diocese)
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in ancient Rome, originally (beginning in the first century B.C.) a municipal district; during the principate, part of a province. From the period of Diocletian, at the end of the third century A.D., the diocese was a large administrative unit including several (up to 16) provinces. A total of 12 dioceses (later 15) were formed. The vicarius, who was subordinate to the praefectus praetorio, headed the diocese.
In the Catholic, and in some Protestant, churches the diocese is a territorial-administrative unit (an eparchy) headed by a bishop.