The correspondence of Voltaire with the King of Prussia, the bond of union in which was their common antipathy to Christianity, forms not the least curious part of the lives of both these eminent men. Nearly all the sovereigns of the Continent, at this period, were led away by this mania, destined to produce such fatal effects to themselves and their children. Catherine of Russia was peculiarly active in the infidel league. De Tocqueville gives the following interesting account of the almost incredible extent to which this mania prevailed in the age which preceded the French Revolution:-- "Voltaire and the King of Prussia resembled two lovers who were continually quarreling and making up their differences. The royal hero could never dispense with the renown which the praises of the Patriarch of Incredulity gave to him. Catherine II. of Russia kept up a close correspondence with him; his expressions to her were confiding, even tender. She required that trumpet to celebrate her exploits, and palliate the crimes committed in the pursuit of her ambition. 'My _Catau_ (his name for the Empress) loves the philosophers, her husband will suffer for it with posterity.' At the same time, she respected him more than Frederick, and her letters were never disgraced by any impurity. She offered D'Alembert to intrust him with the education of her only son, and to settle on him a pension of 50,000 francs (L2000). She flattered Diderot, and sent him a present of 66,000 francs (L2400). If the Encyclopedia is proscribed at Paris, it was reprinted at St Petersburg; the Empress went so far as herself to translate the Belisarius of Marmontel into the Russian tongue. Eighteen other princes, among whom were the King of Poland, the King of Sweden, and the King of Denmark, corresponded with Voltaire, and hastened to deposit in his hands their adhesion to his protest against the prejudices of the age. The princes and great men who were travelling in Europe, endeavoured to stop at Ferney, happy if they could enjoy for a few minutes the conversation of the great writer. 'I have been,' said he to Madame de Deffand, 'for fourteen years the hotel-keeper of Europe.' In his old age, intoxicated with joy, he wrote to Helvetius, on the 26th June 1765: 'Do you not see that the whole North is for us, and that it is inevitable that sooner or later those miserable fanatics of the South must be confounded? The Empress of Russia, the King of Prussia, the conqueror of the superstitious Austrian, besides many other princes, have already erected the standard of philosophy.' Again he wrote to D'Alembert, on the 4th June 1767: 'Men begin to open their eyes from one end of Europe to the other. Fanaticism, which feels its weakness and implores the arm of authority, despite itself, acknowledges its defeat. The works of Bolingbroke, of Trent, and of Boulanger, universally diffused, are so many triumphs of Reason. Let us bless that revolution