IN the Catalogue des écrivains which accompanies the Siècle de Louis XIV, Voltaire remarks of the historian Dupleix:
Il est le premier historien qui ait cité en marge ses autorités; précaution absolument nécessaire quand on n'écrit pas l'histoire de son temps, à moins qu'on ne s'en tienne aux faits connus.1
But this absolutely necessary precaution is one which Voltaire himself never takes. Sometimes he offers excuses, asserting, for example, that the events of the early years of the reign of Louis XIV are too well known to need the citation of authorities, and that he himself has 'witnessed' the closing years. At other times, as in the preface to the Histoire de Russie, he can affirm that 'on cite toujours ses garants',2 though he actually does nothing of the sort. The Essai, too, is devoid of all but the vaguest citation of sources, though here more than anywhere, according to his own principles, they are necessary.
However, when such information as the historical works do give is added to that to be found in the correspondence, in the Dictionnaire Philosophique, in controversial writings like the Supplément au Siècle de Louis XIV, and in the statements of contemporaries, a fairly accurate picture of Voltaire's sources can be obtained. In the case of the Siècle, this task has been largely accomplished by Émile Bourgeois in his edition, though his conclusions may be supplemented by the far more detailed examination to which Lanson has subjected the final chapters of the work.3 In the case of the Essai an introductory investigation on the same lines has been carried out by Hagmann.4
From this point of view Voltaire's works may be divided into____________________