the system of liturgical practices and discipline observed by both the Armenian Apostolic (Armenian Apostolic Church) (Orthodox) Church and the Armenian Catholics (Armenian Catholic Church). The Armenians, who regard themselves as the “first Christian nation,” were converted to Christianity by St. Gregory the Illuminator about AD 300. The Liturgy of St. Gregory the Illuminator, used by both Apostolic and Catholic Armenians, is patterned after the Antiochene Liturgy of St. James (James, Liturgy of Saint) and the Byzantine Liturgy of St. John Chrysostom and is usually divided into five parts: (1) the prayers of preparation in the sacristy, (2) the prayers of preparation in the sanctuary, (3) the preparation of the gifts, (4) the liturgy of the catechumens, and (5) the liturgy of the faithful, culminating in Communion.

Churches of the Armenian rite, unlike Byzantine churches, are generally devoid of icons and, in place of an iconostasis (screen), have a curtain that conceals the priest and the altar during parts of the liturgy. The Communion itself is given in two species, as in other Orthodox churches. For its worship services the Armenian rite is dependent upon such books as the Donatzuitz, the order of service, or celebration of the liturgy; the Badarakamaduitz, the book of the sacrament, containing all the prayers used by the priest; the Giashotz, the book of midday, containing the Epistle and Gospel readings for each day; and the Z'amagirq, the book of hours, containing the prayers and psalms of the seven daily offices, primarily matins, prime, and vespers.