(ostiarius, Lat. ostium, a door.)
Denoted among the Romans the slave whose duty it was to guard the entrance of the house. In the Roman period all houses of the better class had an ostiarius, or ostiary, whose duties were considered very inferior. When, from the end of the second century the Christian communities began to own houses for holding church services and for purposes of administration, church ostiaries are soon mentioned, at least for the larger cities. They are first referred to in the letter of Pope Cornelius to Bishop Fabius of Antioch written in 251 (Eusebius, "H.E.", VI, 43), where it is said that there were then at Rome 46 priests, 7 deacons, 7 subdeacons, 42 acolytes, and 52 exorcists, lectors, and ostiaries, or doorkeepers. According to the statement, of the "Liber Pontificalis" (ed. Duchesne, I, 155) an ostiary named Romanus suffered martyrdom in 258 at the same time as St. Lawrence. In Western Europe the office of the ostiary was the lowest grade of the minor clergy. In a law of 377 of the Codex Theodosianus (Lib. XVI, tit. II, num. XXIV; ed. Gothofredi, VI, I, 57) intended for the Vicariate of Italy, the ostiaries are also mentioned among the clergy who have a right to personal immunity. In his letter of 11 March, 494, to the bishops of southern Italy and Sicily Pope Gelasius says that for admission into the clergy it was necessary that the candidate could read (must, therefore, have a certain amount of education), for without this prerequisite an applicant could, at the most, only fill the office of an ostiary (P.L., LVI, 691). In Rome itself this office attained to no particular development, as a large part of these duties, namely the actual work necessary in the church building, what is now probably the duty of the sexton, was at Rome performed by the mansionarii. The clergy of the three lower grades (minor orders) were united at Rome into the Schola cantorum and as such took part in the church ceremonies. There are no special prayers or ceremonies for the ordination of the lower clergy in the oldest liturgical books of the Roman Church. For the Gallican Rite, short statements concerning the ordination of the lower orders, among them that of the ostiaries, are found in the "Statuta ecclesiæ antiqua" a collection of canons which appeared at Arles about the beginning of the sixth century (Maassen, "Quellen des Kirchenrechts", I, 382). The "Sacramentarium Gelasianum" and the "Missale Francorum" contain the same rite with the prayers used on this occasion.
According to these the ostiaries are first instructed in their duties by the archdeacon; after this he brings them before the bishop who takes the keys of the church from the altar and hands them to the candidate for ordination with the words: "Fulfil thine office to show that thou knowest that thou wilt give account to God concerning the things that are locked away under these keys." Then follows a prayer for the candidate and a prayer for the occasion that the bishop pronounces over him. This ceremony was also at a later date adopted by the Roman Church in its liturgy and has continued with slight changes in the formulæ until now. In Latin Western Europe, outside of Rome, in the late Roman era and the one following, the ostiaries were still actually employed as guardians of the church buildings and of their contents. This is shown by the epitaph of one Ursatius, an ostiary of Trier (Corpus inscr. latin., XIII, 3789). An ostiary of the church of Salona is also mentioned in an epitaph (Corpus inscr. Iatin., III, 13142). Later, however, in the Latin Church the office of ostiary universally remained only one of the degrees of ordination and the actual work of the ostiary was transferred to the laity, (sacristans, sextons, etc.). In the ordination of ostiaries at the present day their duties are thus enumerated in the Pontifical: "Percutere cymbalum et campanam, aperire ecclesiam et sacrarium, et librum ei aperire qui prædicat" (to ring the bell, to open the church and sacristy, to open the book for the preacher). The forms of prayer for the ordination are similar to those in the old Gallican Rite. In the East there were also doorkeepers in the service of the Church. They are enumerated as ecclesiastical persons by the Council of Laodicea (343-81). Like the acolytes and exorcists, they were only appointed to serve the church, but received no actual ordination and were not regarded as belonging to the ecclesiastical hierarchy. According to the "Apostolic Constitutions" belonging to the end of the fourth century the guarding of the door of the church during the service was the duty of the deacons and subdeacons. Thus the doorkeepers exercised their office only when service was not being held.
DUCHESNE, Origines du culte chrétien (5th ed., Paris, 1909). 349 sq.; WIELAND, D. genetische Entwicklung d. sogen. Ordines minores in den drei ersten Jahrhunderten (Rome, 1897), 54 sqq., 161 sqq.; THOMASSINUS, Vetus et nova ecclesiæ disciplina circa beneficia et beneficiarios, pt. i, lib. I, cap. xxx-xxxiii, I (Lyons, ed. 1706), 319 sqq.
J.P. KIRSCH