The Definition of Patriarchal Jurisdictional Spheres in Late Antiquity: Questioning Delimitations (Rome, Constantinople and the Eastern Illyricum)

Abstract The complex genesis of the pentarchy of patriarchal sees within the Late Antique imperial church is well-known. Nevertheless, the outcome of this development is often seen as a unique covering of the Mediterranean world with five spheres of ecclesiastical jurisdiction. Among them, the exceptional preponderance of Rome seems obvious: comprising the so-called Eastern Illyricum, it extended well into the Greek-speaking world. This model is questioned in the present article. In a first step we again discuss the fundamental canons of ecumenical councils (from Nicaea I to Chalcedon) regarding the future patriarchal sees arguing that they concern two different configurations of order: one of them by rank, which distinguishes five sees of exceptional authority leading the imperial church; and a different one regarding territorial spheres of jurisdiction, which were only defined for two of these sees precisely: for Alexandria (Nic I, can. 6) and for Constantinople (Chalc, can. 28). Against this background, we briefly outline the fundamental diversity that characterized the spheres of authority of Rome and of Constantinople throughout the early medieval centuries. In a third step we come back to the position of the Eastern Illyricum in this system, proposing an interpretation that highlights the ambiguity of its position between the two attracting poles of Rome and Constantinople and the quasi-patriarchal position the see of Thessalonike enjoyed, backed by the Roman vicariate. It is proposed to re-consider whether an actual jurisdictional transfer of the Eastern Illyricum from Rome to Constantinople ever happened at all. It was not until the beginning of the tenth century that the position of the Illyrian bishops within the Constantinopolitan synod as basic constituent of this patriarchate was finally defined, to the very detriment of Thessalonike’s position.