(ostiarii), in the ancient Church, a class of church officers forming the lowest clerical order. Their duties were to open and close the doors, not only at the termination of religious worship, but during the services, especially after the missa catechumenorum (q.v.). In later times, in the Roman Church, their duties became nearly those of the modern sexton, viz. to take care of the church ornaments and vessels, to ring the bell, to sweep the church, etc. The customary forms of ordination are prescribed in the fourth council of Carthage; and the keys were delivered to them by the bishop, with the injunction, "Behave thyself as one who must give account to God of the things that are kept locked under these keys." Their ordinary name was πυλωροί, ostiarii, and sometimes mansionarii and janitores. — Bingham, Orig. Eccles. book 3, chapter 6.