The languages of political societies have a central importance for historians of the medieval and modern periods who favour an anthropological approach. When the mounting pressure of war drives cities and kingdoms to develop new fiscal systems, they soon discover that to be easily accepted and hence profitable their demands have to be recognized as legitimate, both in their motives and in their methods of perception. This recognizance can only be achieved through a lengthy, difficult and usually disputed process, a dialogue in which propaganda plays only a minor role: legitimacy is not decided by decree: it depends upon the religious and social values on which individual subjects determine their positions. The continuous cultural transformations which are engendered both by the Gregorian Revolution and the commercial and juridical consequences of the medieval European economic growth allows the development of articulate political languages, which express in words, images and other systems of signs the values and concepts which all those detaining any kind of symbolic power try to manipulate and to turn to their advantage. When dealing with oral and written communication, the historian benefits from the recent developments of discourse analysis, corpus linguistics and the statistical techniques associated with them.