The first diocesan structures in Armenia were formed on the basis of early Christian communities (parishes).
At the beginning of the 4th century, Patriarch Gregory I Illuminator established the first dioceses in the provinces and states of Armenia as bishoprics, inspectorates, pastorates, and dioceses, and appointed leaders to head them, who were called respectively: bishop, Dean, and pastor. The name Diocese is derived from the name of dioceses, the administrative units of the eastern provinces of the Byzantine Empire of the 7th century. The dioceses were headed by archbishops or bishops appointed by the Encyclical of the Armenian Catholicos, managing spiritual, educational, cultural, even social and legal-political issues.
In the 10th century, dioceses subordinate to the Armenian Catholicosate also operated outside of Armenia. There is a mention of the diocese of the Armenian Church abroad since the second half of the 6th century. Prince Smbat Bagratuni, whom the Persian King Khosrov II had appointed as the governor of Vrkan, met many Christians here, including Armenians, and appealed to the Catholicos Movses II of Yeghvard (574-604) to ordain priest Abel as a bishop.
Catholicos Khachik I of Arsharun (973-992) also established dioceses in the cities of Antioch, Tarsus, and Trianopolis. The diocese is named after the region or settlement where the residence of the diocesan primate was.
In the late Middle Ages, due to historical and political circumstances, some dioceses disappeared, and new ones were created by the division or union of others. The big dioceses were split up, gradually gained new territory and influence and turned into independent ecclesiastical-administrative units. Accordingly, new types of dioceses emerged in the Armenian Church: episcopal, inspectorial and monastic, episcopal diocesan inspection, episcopal state, inspection state, leadership, delegate-leadership, leadership vicarage, inspection, state and monastic inspection, vicarage, state pastorate and pastorate.
Under the direction of the Catholicos of All Armenians, Diocesan Primates of the Armenian Church can be not only bishops, but also Proto-Archimandrites and Archimandrites. In different periods, the number of dioceses of the Armenian Church, the name, and the center have changed. The dioceses had an independent or semi-independent state of governance.
Nowdays the Armenian Apostolic Holy Church has dioceses not only in the territory of the Republic of Armenia, but also in many Armenian communities in the Diaspora.
________