M. de la Monnoye, having been informed that a learned German [1] intended to publish a dissertation the object of which was to prove that this work had really been printed, wrote a letter, in refutation, to one of his friends; this letter was given by M. Bayle to M. Basnage de Bauval, who in February 1694, gave an extract from it in his "History of the works of celebrated and learned men." At a later period M. de la Monnoye entered more fully into the subject, in a letter dated at Paris 16th of June, 1712, and addressed to President Bouhier, in which letter, he says, will be found an abridged but complete account of this remarkable book. He condemns at once the opinion of those who attribute the work to the Emperor Frederick. The false charge, he says, took its rise from a passage in the appendix to a discourse concerning Antichrist, and published by Grotius, wherein he speaks as follows [2]: "Far be it from me to attribute the book called 'The Three Impostors,' either to the Pope, or to the opponents of the Pope; long ago the enemies of the Emperor Frederick Barbarossa set abroad the report of such a book, as having been written by his command; but from that period nobody has seen it; for which reason I consider it apocryphal." Colomiez quotes this, page 28 of his "Historical Miscellanies;" but he adds that there are some blunders--that it was not Frederick I. (Barbarossa,) on whom they intended to fix the authorship, but Frederick II. his grandson. This he says, is apparent from the letters of Pierre des Vignes, the secretary and chancellor of the second Frederick, and from Matthew Paris; inasmuch as they record, that this monarch was blamed for having said that the world had been led aside by "Three Impostors;" but by no means that he had written a book having such a title. The Emperor denied in the strongest terms, that he ever made use of any expression to that effect. He detested the blasphemy with which they charged him, and declared that it was an atrocious calumny; more shame to Lipsius and other writers who have condemned him without sufficiently looking into the evidences. Averroes, nearly a century previous, had jeered at the three religions, saying [3]; that "the Jewish religion was a law for children; the Christian religion a law which it was impossible to follow; and the Mahometan religion a law in favor of swine." [4] Since then, many people have written with great freedom on this same subject. We read in the works of Thomas de Catimpre, that M. Simon de Tournay had said that "Three Seducers"--Moses, Jesus Christ, and Mahomet, had "mystified mankind with their doctrines." This is evidently the M. Simon de Churnay, of whom Matthew Paris relates some other improprieties, and the same individual whom Polydore Virgil styles de Turwai, the orthography in both instances having been mismanaged.