The transformation of the model of university organization, with the passage of the traditional system of chairs to departmental, began in Spain in the mid-sixties. The educational policy of the regime, taking as reference foreign models such as the German or Anglo-Saxon, introduces via regulations, which are not real and operative, the bases of the new model through the Law of July 17, 1965 on the structure of university faculties and their teaching staff. This article analyses and discusses that initial process of gestation and insertion of the department as a new structure of the hierarchical-administrative organization of the institution, taking the University of Salamanca as an excellent illustration of this case study. For this, the historical method and unpublished printed sources are used -- minutes of the Council of Rectors, of Faculty Meetings, correspondence, etc. -- as well as legislative sources, which provide us with the basic normative frame of reference. All this allows us to review the main legal milestones and some of the most relevant events that take place prior and subsequent approval of the departmental system, issues that will reveal motivations, points of view and tensions generated among the body of professors before the loss of chairs turned into authentic bastions.