THE ancient Vedic literature, the foundation of the whole literature of India, which has been handed down in that country in an unbroken succession from the earliest times within the recollection of man to the present day, became known for the first time beyond the frontiers of India through the Upanishads. The Upanishads were translated from Sanskrit into Persian by, or, it may be, for Dârâ Shukoh, the eldest son of Shâh Jehân, an enlightened prince, who openly professed the liberal religious tenets of the great Emperor Akbar, and even wrote a book intended to reconcile the religious doctrines of Hindus and Mohammedans. He seems first to have heard of the Upanishads during his stay in Kashmir in 1640. He afterwards invited several Pandits from Benares to Delhi, who were to assist him in the work of translation. The translation was finished in 1657. Three years after the accomplishment of this work, in 1659, the prince was put to death by his brother Aurangzib, in reality, no doubt, because he was the eldest son and legitimate successor of Shâh Jehân, but under the pretext that he was an infidel, and dangerous to the established religion of the empire.
When the Upanishads had once been translated from Sanskrit into Persian, at that time the most widely read language of the East and understood likewise by many European scholars, they became generally accessible to all who took an interest in the religious literature of India. It is true that under Akbar's reign (1556-1586) similar translations had been prepared, but neither those nor the translations of Dârâ Shukoh attracted the attention of European scholars till the year 1775. In that year Anquetil Duperron, the famous traveller and discoverer of the Zend-avesta, received one MS. of the Persian translation of the Upanishads, sent to him by M. Gentil, the French resident at the court of Shuja ud daula, and brought to France by M. Bernier. After receiving another MS., Anquetil Duperron collated the two, and translated the Persian translation into French (not published), and into Latin. That Latin translation was published in 1801 and 1802, under the title of Oupnek'hat, id est, Secreturn tegendum: opus ipsa in India rarissimum, continens antiquam et arcanam, seu theologicam et philosophicam doctrinam, e quatuor sacris Indorum libris Rak baid, Djedjer baid, Sam baid, Athrban baid excerptam; ad verbum, e Persico idiomate, Samkreticis vocabulis intermixto, in Latinum conversum: Dissertationibus et Annotationibus difficiliora explanantibus, illustratum: studio et opera Anquetil Duperron, Indicopleustæ. Argentorati, typis et impensis fratrum Levrault, (vol. i, 1801; vol. ii, 1802).
This translation, though it attracted considerable interest among scholars, was written in so utterly unintelligible a style, that it required the lynxlike perspicacity of an intrepid philosopher, such as Schopenhauer, to discover a thread through such a labyrinth. Schopenhauer, however, not only found and followed such a thread, but he had the courage to proclaim to an incredulous age the vast treasures of thought which were lying buried beneath that fearful jargon.
As Anquetil Duperron's volumes have become scarce, I shall here give a short specimen of his translation, which corresponds to the first sentences of my translation of the Khândogya-upanishad (p. 1):—
Schopenhauer not only read this translation carefully, but he makes no secret of it, that his own philosophy is powerfully impregnated by the fundamental doctrines of the Upanishads. He dwells on it again and again, and it seems both fair to Schopenhauer's memory and highly important for a true appreciation of the philosophical value of the Upanishads, to put together what that vigorous thinker has written on those ancient rhapsodies of truth.
In his Welt als Wille und Vorstellung, he writes, in the preface to the first edition, p. xiii:
This may seem strong language, and, in some respects, too strong. But I thought it right to quote it here, because, whatever may be urged against Schopenhauer, he was a thoroughly honest thinker and honest speaker, and no one would suspect him of any predilection for what has been so readily called Indian mysticism. That Schelling and his school should use rapturous language about the Upanishads, might carry little weight with that large class of philosophers by whom everything beyond the clouds of their own horizon is labelled mysticism. But that Schopenhauer should have spoken of the Upanishads as “products of the highest wisdom” “(Ausgeburt der höchsten Weisheit)”, that he should have placed the pantheism there taught high above the pantheism of Bruno, Malebranche, Spinoza, and Scotus Erigena, as brought to light again at Oxford in 1681, may perhaps secure a more considerate reception for these relics of ancient wisdom than anything that I could say in their favour.
 Elphinstone, History of India, ed. Cowell, p. 610.
 M. M., Introduction to the Science of Religion, p. 79.
 Several other MSS. of this translation have since come to Iight; one at Oxford, Codices Wilsoniani, 399 and 400. Anquetil Duperron gives the following title of the Persian translation: “Hanc interpretationem [tôn] Oupnekhathai quorumvis quatuor librorum Beid, quod, designatum cum secreto magno (per secretum magnum) est, et integram cognitionem luminis luminum, hic Fakir sine tristitia (Sultan) Mohammed Dara Schakoh ipse, cum significatione recta, cum sinceritate, in tempore sex mensium (postremo die, secundo [toû] Schonbeh, vigesimo) sexto mensis [toû] Ramazzan, anno 1067 [toû] Hedjri (Christi, 1657) in urbe Delhi, in mansione nakhe noudeh, cum absolutione ad finem fecit pervenire.” The MS. was copied by Âtma Ram in the year 1767 A.D. Anquetil Duperron adds: “Absolutum est hoc Apographum versionis Latinæ [tôn] quinquaginta Oupnekhatha, ad verbum, e Persico idiomate, Samskreticis vocabulis intermixto, factæ, die 9 Octobris, 1796, 18 Brumaire, anni 4, Reipublic. Gall. Parisiis.”
 M. M., History of Ancient Sanskrit Literature, second edition, p.325.
 Schopenhauer, Parerga, third edition, II, p.426.
 Loc. cit. II, pp. 425.
 Loc. cit. I, p. 59.]
 Loc. cit. 11, p.428.
 Loc. cit. I, p. 6. These passages were pointed out to me by Professor Noiré.