For the modern reader, the use of direct speech, which is normally fictional, is one of the most remarkable features of ancient historiography. On the basis of a study of the rhetorical form and of the motifs employed in speeches by Herodotus and Thucydides, the author is able to expound systematically for the first time the similarities and differences in the employment of this characteristic tool in the works of the two historians, and to undertake a comparison with the options available to modern historical works.