It is useless to discuss what can never be ascertained, who the author of the Desátir was. But this work would be unintelligible without the Persian translation and commentary. Silvestre de Sacy asks: “Are not this translation and this commentary, themselves pseudonymous and apocryphal books, and is not the whole, perhaps, the work of an impostor of the last century?” In answering this, I shall be guided by the baron von Hammer, who wrote his review of the Desátir before he had seen that of the _Journal des Savans_, but, after having perused the latter, declared that he had nothing to change in his opinion. Although the commentator, to whom the honor of being the inventor of the Mahabadian language is ascribed, follows in the main the ancient text word for word, and substitutes commonly a new for the obsolete form of the term, yet frequent instances occur (some of which baron von Hammer adduces) which prove that the interpreter did not clearly understand the old text, but in place of the true meaning gave his own arbitrary interpretation. The proper names even are not always the same. Besides――and this is most important――the doctrines contained in the Desátir and in the Commentary differ from each other. In the books of the first Mahabadian kings we find the fundamental ideas of the Oriental philosophy, such as it was before its migration from Asia to Europe; but in the commentary we perceive the development of the Aristotelian scholastic, such as it formed itself among the Asiatics, when they had, by means of translations, become acquainted with the Stagirite. We shall revert to this subject hereafter. Whatever it be――the discrepancies between the original text and the interpretation, as they would certainly have been avoided by the author of both, prove that they are the works of two different persons, probably with the interval of a few centuries between them.