The distinction between clerical and lay appeared early in the history of the Church as a natural influence of pagan and Jewish practice, and is assumed by Clement of Rome, who, however, makes an important point when he treats the laity as an order: “to the high priest his proper ministrations are allotted, and to the priests the proper place has been allotted, and on levites their proper services have been imposed; the layman is bound by the ordinances for the laity.” In course of time the gulf widened between clergy and laity and the laity degenerated into mere spectators, the liturgy being in the hands of the clergy. The distinction is sufficiently plain in Tertullian and Origen. The conception of opus operatum, though not intended to exclude the co-operation either of the celebrant or of the receiver, had the practical effect of setting the people a great distance away; and lay communion in one kind, though this was not its motive, seemed to symbolise the separation.