The contribution deals with the de jure public authority that the bishops of Trieste held in the city from 948, when it was granted to the then Bishop John by King Lothar II of Italy, to the end of the thirteenth century with partial loss of their jurisdictions in the middle of the century. Whereas several written sources that have been preserved from the said period reveal various aspects of the bishops’ actions, a proper interpretation of sources that do not deal directly with their government may supplement our understanding of relations between various political actors both in the city itself and its wider surroundings. Although this question has been addressed by several Trieste historians over the last century and a half, their interest has been limited to only certain sources and hence only certain aspects of public authority exercised by the bishops of Trieste.