In his Essai sur les moeurs, Voltaire devotes a few chapters on Persia, from its Antiquity to contemporary times. All involve implicitly the same stakes: lead a polemical debate against the Judaeo-Christian roots of European religion, or against some aspects of French political climate. Using travel stories as Chardin’s Voyage en Perse as well as erudite sources as Thomas Hyde Veterum Persarum religionis historia or recent histories of Persian revolutions, Voltaire conscientiously selects the facts, remarks or religious statements which draw an image of a ‘modern’ Persia, in advance in religious and social matters, and reject the horrific image of despotism imposed by Montesquieu.