It is impossible in the present day to doubt the existence of "The Three Impostors," since we find several manuscript copies of it. If M. de la Monnoye had observed the agreement of it with an extract published at Leyden, 1st. Jan. 1716,--the same division into six chapters--the same titles, and the same subjects of which they treat, he would have exclaimed against the forgery of this work, improperly attributed to Pierre des Vignes, the Secretary and Chancellor of Frederick II. This judicious critic long ago observed the difference between the Gothic style of Pierre des Vignes in his Epistles, and that of the letter pretended to be addressed to the Duke of Bavaria, "Otho the illustrious," when they sent him the work. A more important point has not escaped the notice of the learned. This treatise is written and argued in the method and upon the principles of the New Philosophy, which was not introduced until about the middle of the seventeenth century, after Descartes, Gassendi, Bernier, and some others had explained its principles in a juster and clearer way than did the ancient philosophers, who wished to preserve their secrets, as they affected a mysterious obscurity in favor of the initiated. The author himself, in the fifteen chapter of his work, names Descartes, and combats the arguments of this great man on the subject of the soul. Neither Pierre des Vignes, nor any of those whom they have attempted to pass off as the author of this book, could have reasoned according to the principles of the new Philosophy, which was not introduced till after they had written. To whom then must the work be attributed? We must conclude that it cannot be of the same date as the short letter printed at Leyden, 1717. But another difficulty occurs. Tentzelius, who wrote in 1689, also gives an extract from this book upon the credit of a pretended ocular witness. But without attempting to fix the date of this book, which is said to have been composed in Latin and printed; the small French manuscript treatise, whether it had ever been written in that language or whether it is translated from the Latin, (which is difficult to believe,) cannot be of a very ancient date.