BISHOPRIC, or DIOCESE: The territory over which the jurisdiction of a bishop extends. The origin of such divisions goes back to the foundation and growth of the very early Christian communities. When the apostles founded a church in a city, the faithful living there (Gk. paroikoi, parepidēmoi; cf. Eph. ii, 19; I Pet. ii, 11) formed a community (paroikia) which gradually took more definite shape under the leadership of the presbyters or bishops, and gained adherents outside the town. At first these latter attended divine service in the city, until their numbers increased sufficiently to form a separate dependent community, the term paroikia being applied to the larger territory equally. In the West the name parochia retained this sense until the ninth century, when it became restricted to single parishes in the modern sense, the bishop's jurisdiction being known as diæcesis (already in use to designate a civil governor's jurisdiction). The latter word in the East, following the analogy of civil divisions, was applied to the district ruled by a patriarch. In Gaul the ecclesiastical unit was constituted out of the chief town of a district and its annexed territory (conventus, Gk. dioikēsis), which in the Frankish period corresponded to the jurisdiction of a count. In Germany the original diocese was larger, and the Gau was coterminous with its subdivision of archdeaconry or deanery. The erection or redistribution of dioceses was from the fourth century a function of the metropolitan and the provincial synod; in Germany from the eighth century it was carried out under papal supervision. From the eleventh century it has been reserved to the pope; but in Germany the joint action of the state has been required, the matter being considered a causa mixta.
Bibliography: L. Thomassin, Vetus et nova ecclesiæ, disciplina, part I, book iii, Lucca, 1728; R. Hooker, Ecclesiastical Polity, book viii, chap. 8, best ed., by Keble, 3 vols., Oxford, 1845; H. Milman, History of Christianity, book iv, London, 1867; W. T. Arnold, Roman System of Provincial Administration, London, 1879; Bingham, Origines, Books iv–v, ix; KL, ii, 878-888.