Communal structures of medieval commune of Braĉ are one of the most complex within the entire spectrum of eastern Adriatic, although they are at the same time one of the poorly discussed aspects of Croatian medieval historiography. By examining the broader geomorphological, architectonic, intellectual, and economic implications in comparison with the relationship with the surrounding communes of Hvar and Split, we realize that the underlying generators in the formation of communes are realized in the form of social topography and spatial organization. These two aspects, as some sorts of modifiers and generators since the prehistoric times, both antiquity and late antiquity, have enabled extremly particular socio – spatial distinctions, which will only be fully expressed in the mature commune, around 1420. The aim of this paper is to articulate key stages in the process of creating a commune of Braĉ, aiming to achieve an interdisciplinary approach in order to synthetically attempt to enrich the image of Middle Dalmatian medieval space. Analysis of the problem is thus focused on the presentation of relevant factors, which primarily led to the creation of a monistic organization of society with distinct Slavic characteristics, while spatial significance is seen in terms of the double – diametric direction of settlement. Defining the separateness of the medieval commune of Braĉ enables a timely construction of the distinctive design and activity model on an Eastern Adriatic island commune.