k: dioikein], "to keep house," "to govern"), the
sphere of a bishop's jurisdiction. In this, its sole modern sense, the
word diocese (_dioecesis_) has only been regularly used since the 9th
century, though isolated instances of such use occur so early as the
3rd, what is now known as a diocese having been till then usually called
a _parochia_ (parish). The Greek word [Greek: dioikesis], from meaning
"administration," came to be applied to the territorial circumscription
in which administration was exercised. It was thus first applied e.g. to
the three districts of Cibyra, Apamea and Synnada, which were added to
Cilicia in Cicero's time (between 56 and 50 B.C.). The word is here
equivalent to "assize-districts" (Tyrrell and Purser's edition of Cicero
_Epist. ad fam._ iii. 8. 4; xiii. 67; cf. Strabo xiii. 628-629). But in
the reorganization of the empire, begun by Diocletian and completed by
Constantine, the word "diocese" acquired a more important meaning, the
empire being divided into twelve dioceses, of which the
largest--Oriens--embraced sixteen provinces, and the
smallest--Britain--four (see ROME: _Ancient History_; and W. T. Arnold,
_Roman Provincial Administration_, pp. 187, 194-196, which gives a list
of the dioceses and their subdivisions). The organization of the
Christian church in the Roman empire following very closely the lines of
the civil administration (see CHURCH HISTORY), the word diocese, in its
ecclesiastical sense, was at first applied to the sphere of
jurisdiction, not of a bishop, but of a metropolitan.[1] Thus Anastasius
Bibliothecarius (d. c. 886), in his life of Pope Dionysius, says that he
assigned churches to the presbyters, and established dioceses
(_parochiae_) and provinces (_dioeceses_). The word, however, survived
in its general sense of "office" or "administration," and it was even
used during the middle ages for "parish" (see Du Cange, _Glossarium_, s.
"Dioecesis" 2).

The practice, under the Roman empire, of making the areas of
ecclesiastical administration very exactly coincide with those of the
civil administration, was continued in the organization of the church
beyond the borders of the empire, and many dioceses to this day preserve
the limits of long vanished political divisions. The process is well
illustrated in the case of English bishoprics. But this practice was
based on convenience, not principle; and the limits of the dioceses,
once fixed, did not usually change with the ch