"One of the features of the modern state in its early phase is the development of distinctively political societies: in both Italian cities (from the 12th century) and western monarchies (from the late 13th), exclusively interpersonal links or the arbitral powers of family or social group leaders, although still important, had to compete with other sources of authority. All decisions about justice, war and taxation had to be accepted by those who were directly, and in some cases indirectly, concerned by them. This process, its institutionalisation through representative assemblies and administrative devices, the crises often violent to which it led, has been scrutinized by historians of late. However, scholars have as yet paid little attention to the changes in the communication system which this process implied. They have moved within the limited and well-trodden space of the history of political ideas, running the risk of anachronism by using concepts such as those of propaganda or public opinion. This project is based upon a semiotic hypothesis; it aims at answering three questions, with a specific methodology. The semiotic hypothesis is that, in any society, the communication system has a functional structure similar to that of the language (which is part of it): each component can only be understood in relation with others, in a global and synchronic approach necessary to study the idéel defined by Godelier as a combination of the imaginary and of the symbolic. The questions centre upon the process of legitimization, the concept of acceptance, and the relation of political societies to the components of the communication system. The methodology is based upon comparative history and the use of computing techniques (prosopography, textometrics, statistics)."