If an image were needed to evoke the power of the speech, it could be that of Hercules Ogmios leading to a procession whose ears are chained to his tongue. Emblem of the force of eloquence, it is under the aegis of this Gallic Hercules that we place our reflection here to try to grasp the nature of these chains by which the author captivates his audience: how the text is made irresistibly convincing and persuasive to make the reader follow the path of the seductive author? The image clearly communicates the power that this power confers on others and recalls the distrust that this art of conviction has aroused: could this tool be misguided and, manipulating the credulity of the listeners, convince of the veracity of the wrong?
The study of the processes of eloquence has more recently taken on a new force with the linguistic turn; the power of words, the power of language are again fully recognized as inseparable from the contents of speech. The studies proposed here which concern medieval and classical Spain, will make it possible to evaluate the great diversity of the textual and contextual elements which take precedence in order to unmask the springs which aim at winning the adhesion of the reader and to build the appearance of a truth.