The project SOCIOMA aims to write a history of sociological knowledges in Latin Europe of the 12th-15th centuries. This research will distinguish itself from other social history studies by focusing on the study of classificatory thoughts, in order to show that these are not only descriptive, but that they are performative intellectual tools, a repertory of social forms available to the actors, a "technology of power". Adopting a comparative (transnational) and multidisciplinary approach, this project intends to mobilize the analytical tools of sociology and social anthropology, applied to the study of unpublished medieval documentary material held in European libraries. Three axes guide this research program: a lexicographical survey devoted to the vocabulary of social categories; the study and editing of theological, legal, philosophical and medical scholarly texts that convey a discourse on the architectonics of medieval society; and the observation of the use of social taxonomies in the literature of praxis, in order to better reveal the social dynamics that result from them. This project is therefore part of the most recent historiography, observing the new 'governmental rationalities' that developed from the 12th century onwards, under the combined effect of the Gregorian Reformation, the emergence of modern States, and the rediscovery of the sciences of politics. Ambitious in its aspiration to give an account of very current principles of general sociology, it intends to participate in contemporary reflection on the methodology of socio-professional classifications and their political and administrative consequences.