The hierarchy is the collective body of the ecclesiastical ranks including bishops (patriarchs, metropolitans, and bishops), priests (presbyter and hegumen), and deacons (archdeacons and deacons). The rite of ordination of each rank prescribes the role of each member. The ecumenical councils issued several decrees in order to organize their work.
In the fifth century, a writing ascribed to Dionysus the Aeropagite was entitled The Ecclesiastical Hierarchy; chapter 5 of his work presents and interprets the ceremony of the consecration of those in the hierarchy. The author compares the Church clergy with the celestial hierarchy. In the 12th and 13th centuries, Ibn al-Assal in his nomocanon codified all the previous texts taken from the councils, canons, and tradition.