The essay is divided into two parts. The first part portrays the Upper Adriatic, from Ravenna and Venice to the coastal towns in Istria and Dalmatia, as a unified peripheral area. Despite the shifting political context, the socio-cultural composition of the local communities shows similar features because of the ecology of the region and its common Byzantine legacy. Simultaneously, the institutional apparatus demonstrates a high degree of hybridization with the political regimes in the mainland. Some considerations about the impact of international policy on the area are made here. The relevance of the Treaty of Aachen is rethought, and the internal fights for power of the emerging Venetian elites are explained in the light of the building-process of an independent duchy where the control for strategic local resources was a priority. Drawing on older and newer literature, the second part describes the multiple connections between the newly established Venetian political entity and the Istrian peninsula. Patrimonial, commercial and institutional links are considered, and the twofold administrative dependency of Istria from the Church of Grado, i.e., the metropolitan see of Venice, and the Lombard and Frankish rulers is reviewed. What emerges is the agency of an unruly Istrian aristocracy and, above all, the on- and off- control exerted by the Carolingians. In this frame, and in the frame of the above-mentioned Venetian-Istrian connections, the essay moves on to considering the enigmatic figure of the duke John of the Plea of Rižana. In contrast to the traditional interpretation, set of evidence is provided in support of the thesis of his local origin. Even more so, the brand-new hypothesis that he might have come from the nearby duchy of Venice is put forward for future debate.