It is thoroughly characteristic of Diderot's dreamy, heedless humour, and of the sincerity both of his interest in his work for its own sake, and of his indifference to the popular voice, that he should have allowed this, like so many other pieces, to lie in his drawer, or at most to circulate clandestinely among three or four of his more intimate friends. It was written about 1760, and ingenious historians have made of it a signal for the great crusade against the Church. In truth, as we have seen, it was a strictly private performance, and could be no signal for a public movement. _La Religieuse_ was undoubtedly an expression of the strong feeling of the Encyclopaedic school about celibacy, renunciation of the world, and the burial of men and women alive in the cloister. The circumstances under which the story was written are worthy of a word or two. Among the friends of Madame d'Epinay, Grimm, and Diderot was a certain Marquis de Croismare. He had deserted the circle, and retired to his estates in Normandy. It occurred to one of them that it would be a pleasant stratagem for recalling him to Paris, to invent a personage who should be shut up in a convent against her will, and then to make this personage appeal to the well-known courage and generosity of the Marquis de Croismare to rescue her. A previous adventure of the Marquis suggested the fiction, and made its success the more probable. Diderot composed the letters of the imaginary nun, and the conspirators had the satisfaction of making merry at supper over the letters which the loyal and unsuspecting Marquis sent in reply. At length the Marquis's interest became so eager that they resolved that the best way of ending his torment was to make the nun die. When the Marquis de Croismare returned to Paris, the plot was confessed, the victim of the mystification laughed at the joke, and the friendship of the party seemed to be strengthened by their common sorrow for the woes of the dead sister. But Diderot had been taken in his own trap. His imagination, which he had set to work in jest, was caught by the figure and the situation. One day while he was busy about the tale, a friend paid him a visit, and found him plunged in grief and his face bathed in tears. "What in the world can be the matter with you?" cried the friend. "What the matter?" answered Diderot in a broken voice; "I am filled with misery by a story that I am writing!" This capacity of thinking of imaginary personages as if they were friends living in the next street, had been stirred by Richardson. His acquaintances would sometimes notice anxiety and consternation on his countenance, and would ask him if anything had befallen his health, his friends, his family, his fortune. "O my friends," he would reply, "Pamela, Clarissa, Grandison ...!" It was in their world, not in the Rue Taranne, that he really lived when these brooding moods overtook him. And while he was writing _The Nun_, Sister