In order to understand history as it has been practised in the twentieth century, we must go back in time. Not necessarily to Herodotus and Thucydides, nor even to the great founding figures of the ages of learning and of the Enlightenment, however enduring their influence. But to those historians who in the course of the nineteenth century brought to its conclusion the radical renewal of knowledge about the past: the means that enabled them to acquire it, arguments which were accepted as proofs, conceptual frameworks supposed to make deeds intelligible, ways of talking about times past - to historians who integrated this knowledge that was formerly split between literature, learned research and theology supplanted by philosophy, around a discipline comparable to philology as much from the epistemological point of view as in terms of status and driven not only by ambition to retain the exclusive right to the term history but also, very early, by that of conquering a superior position in the world of science.