In short, the monarchs of the north understood and used the new forces of the men of letters, whom their own sovereign only recognised to oppress. The contrast between the liberalism of the northern sovereigns, and the obscurantism of the court of France, was never lost from sight. Marmontel's _Belisarius_ was condemned by the Sorbonne, and burnt at the foot of the great staircase of the Palace of Justice; in Russia a group of courtiers hastened to translate it, and the Empress herself undertook one chapter of the work. Diderot, who was not allowed to enter the French Academy, was an honoured guest at the Russian palace. For all this Catherine was handsomely repaid. When Diderot visited St. Petersburg, Voltaire congratulated the Empress on seeing that unique man; but Diderot is not, he added, "the only Frenchman who is an enthusiast for your glory. We are lay missionaries who preach the religion of Saint Catherine, and we can boast that our church is tolerably universal."[79] We have already seen Catherine's generosity in buying Diderot's books, and paying him for guarding them as her librarian. "I should never have expected," she says, "that the purchase of a library would bring me so many fine compliments; all the world is bepraising me about M. Diderot's library. But now confess, you to whom humanity is indebted for the strong support that you have given to innocence and virtue in the person of Calas, that it would have been cruel and unjust to separate a student from his books."[80] "Ah, madam," replies the most graceful of all courtiers, "let your imperial majesty forgive me; no, you are not the aurora borealis; you are assuredly the most brilliant star of the north, and never was there one so beneficent as you. Andromeda, Perseus, Callisto are not your equals. All these stars would have left Diderot to die of starvation. He was persecuted in his own country, and your benefactions came thither to seek him! Lewis XIV. was less munificent than your majesty: he rewarded merit in foreign countries, but other people pointed it out to him, whereas you, madame, go in search of it and find it for yourself. Your generous pains to establish freedom of conscience in Poland are a piece of beneficence that the human race must ever celebrate."[81] [79] November 1, 1773. [80] November 1766. [81] December 22, 1766.