ame
thing. Congregational episcopacy was the rule for a number of
generations. But after the middle of the 3rd century diocesan episcopacy
began to make its appearance here and there, and became common in the
4th century under the influence of the general tendency toward
centralization, the increasing power of city bishops, and the growing
dignity of the episcopate (cf. canon 6 of the council of Sardica, and
canon 57 of the council of Laodicea; and see Harnack, _Mission und
Ausbreitung_, pp. 319 seq.). This enlargement of the bishop's parish and
multiplication of the churches under his care led to a change in the
functions of the presbyterate. So long as each church had its own bishop
the presbyters constituted simply his council, but with the growth of
diocesan episcopacy it became the custom to put each congregation under
the care of a particular presbyter, who performed within it most of the
pastoral duties formerly discharged by the bishop himself. The
presbyters, however, were not independent officers. They were only
representatives of the bishop, and the churches over which they were set
were all a part of his parish, so that the Cyprianic principle, that the
bishop is necessary to the very being of the Church, held good of
diocesan as well as of congregational episcopacy. The bishop alone
possessed the right to ordain; through him alone could be derived the
requisite clerical grace; and so the clergy like the laity were
completely dependent upon him.

The growth of the diocesan principle promoted the unity of the churches
gathered under a common head. But unity was carried much further than
this, and finally resulted in at least a nominal consolidation of all
the churches of Christendom into one whole. The belief in the unity of
the entire Church had existed from the beginning. Though made up of
widely scattered congregations, it was thought of as one body of Christ,
one people of God. This ideal unity found expression in many ways.
Intercommunication between the various Christian communities was very
active. Christians upon a journey were always sure of a warm welcome and
hospitable entertainment from their fellow-disciples. Messengers and
letters were sent freely from one church to another. Missionaries and
evangelists went continually from place to place. Documents of various
kinds, including gospels and apostolic epistles, circulated widely. Thus
in various ways the feeling of unity found expression, and the