In 1745 there had just appeared a sort of romance entitled _Notes towards the History of Persia_, which was attributed, not without some reason, to Madame de Vieux-Maisons. The book contained a story within a story, in which the mysterious prisoner, who was beginning to be talked about everywhere, was identified with the Duke de Vermandois, and to this fact was due the sensation which the book caused. Voltaire immediately saw how he could turn the circumstance to account. He had himself at one time been confined in the Bastille, which was one reason for speaking of it; but he did not dare put in circulation suddenly, without some preparation, the terrible story he had just conceived, and, with a very delicate sensitiveness to public opinion, he contented himself with printing the following paragraph in the first edition of his _Age of Louis XIV._: "A few months after the death of Mazarin there occurred an event which is unexampled in history, and, what is not less strange, has been passed over in silence by all the historians. There was sent with the utmost secrecy to the château of the Isle of Sainte-Marguerite, in the Sea of Provence, an unknown prisoner, of more than ordinary height, young, and with features of rare nobility and beauty. On the way, this prisoner wore a mask the chinpiece of which was fitted with springs of steel, which allowed him to eat freely with the mask covering his face. The order had been given to kill him if he uncovered. He remained in the island until an officer in whom great confidence was placed, named Saint-Mars, governor of Pignerol, having been made governor of the Bastille, came to the Isle of Sainte-Marguerite to fetch him, and conducted him to the Bastille, always masked. The Marquis de Louvois saw him in the island before his removal, and remained standing while he spoke to him, with a consideration savouring of respect." Voltaire, however, does not say who this extraordinary prisoner was. He observed the impression produced on the public by his story. Then he ventured more boldly, and in the first edition of his _Questions on the Encyclopædia_ insinuated that the motive for covering the prisoner's face with a mask was fear lest some too striking likeness should be recognized. He still refrained from giving his name, but already everyone was on tip-toe with the expectation of startling news. At last, in the second edition of _Questions on the Encyclopædia_, Voltaire intrepidly added that the man in the mask was a uterine brother of Louis XIV., a son of Mazarin and Anne of Austria, and older than the king. We know what incomparable agitators of public opinion the Encyclopædists were. Once hatched, the story was not long in producing a numerous progeny, which grew in their turn and became a monstrous brood.