The subject of this paper is the interpretation of the main trends in the development of church organization in the 4th century in modern Orthodox and Catholic historiography. The analysis of the works of Orthodox (N. Afanasiev, J. Meyendorff) and Catholic (V. Monachino, C. Vogel, V. Twomey, K. Schatz, F. Dvornik) church historians and theologians allows us to find a number of specific confessional prejudgments which have some influence on the studies of the historical material. Orthodox authors pay great attention to the problem of the autonomy of the local church. We also can fi nd certain «democratism» in explaining the mechanisms of decision-making and criticism of the idea of institutional authority over local churches (whether papal, synodal or emperor’s authority). The focus of Catholic authors is the idea of communion of local churches, which has hierarchical structure. The source and the leader of this communion is the Roman chair. Growing influence of Rome and canonical legalization of the idea of primacy are considered as the most important tools in Church’s fight for its freedom against the emperor’s control, as well as for its unity against the regionalization of church order (the development of patriarchates). Thus, in the works of the church historians we can see the echoes of the Catholic-Orthodox theological debates about the relationship between the principles of universal primacy and regional autocephalism in church order.