In the Roman period all houses of the better class had an ostiarius, or ostiary, whose duties were considered very inferior.    From Wordnik.com.  [The Catholic Encyclopedia, Volume 12: Philip II-Reuss] Reference

Theoretically, the actual ringing of the bells should be performed by the ostiarius and in the conferring of this minor order the cleric is given a bell to ring, but for centuries past his functions have everywhere become obsolete, and lay bell-ringers have been almost exclusively employed.    From Wordnik.com.  [The Catholic Encyclopedia, Volume 2: Assizes-Browne] Reference

IX, 133) enumerates the orders of the clergy as ostiarius, fossorius, lector, etc.    From Wordnik.com.  [The Catholic Encyclopedia, Volume 6: Fathers of the Church-Gregory XI] Reference

(ostiarius, Lat. ostium, a door.).    From Wordnik.com.  [The Catholic Encyclopedia, Volume 12: Philip II-Reuss] Reference