we can see that historical periodization belongs to an obsession that is characteristic of modernity. Periodization is a way of placing events in a diachrony, and diachrony is ruled by the principle of revolution. In the same way that modernity contains the promise of its overcoming, it is obliged to mark, to date, the end of one period and the beginning of the next. Since one is inaugurating an age reputed to the entirely new, it is right to set the clock to the new time, to start it from zero again. In Christianity, Cartesianism or Jacobinism, this same gesture designates a Year One, that of revelation and redemption in the one case, of rebirth and renewal in the second, or again of revolution and reappropriation of liberties.