The first of the series is _Yaqub b. Ishaq al-Kindi_ (d. circ. 260 A.H. = 873 A.D.), who began very much as a Mu`tazilite interested in the theological problems discussed by the members of that school of thought, but desirous of testing and examining these more accurately, made use of the translations taken directly from the Greek and then only recently published. By this means he brought a much stricter method to bear, and thus opened the way to an Aristotelian scholarship much in advance of anything which had been contemplated so far. As a result his pupils and those who came after them raised new questions and ceased to confine themselves to Mu`tazilite problems, and al-Kindi was their intellectual ancestor in those new enquiries which his methods and his use of the Greek text alone made possible. It is a strange fact that al-Kindi, the parent of Arabic philosophy, was himself one of the very few leaders of Arabic thought who was a true Arab by race. For the most part the scientists and philosophers of the Muslim world were of Persian, Turkish, or Berber blood, but al-Kindi was descended from the Yemenite kings of Kinda (cf. genealogy quoted from the _Tarikh al-Hakama_ cited in note (22) of De Slane’s trans. of Ibn Khallikan, vol. i. p. 355). Very little is known about his life, save that his father was governor of Kufa, that he himself studied at Baghdad, under what teachers is not known, and stood high in favour with the Khalif Mu`tasim (A.H. 218-227). His real training and equipment lay in a knowledge of Greek, which he used in preparing translations of Aristotle’s _Metaphysics_, Ptolemy’s _Geography_, and a revised edition of the Arabic version of Euclid. Besides this he made Arabic abridgments of Aristotle’s _Poetica_ and _Hermeneutica_, and Porphyry’s _Isagoge_, and wrote commentaries on Aristotle’s _Analytica Posteriora_, _Sophistica Elenchi_, the _Categories_, the apocryphal _Apology_; on Ptolemy’s _Almagesta_ and Euclid’s _Elements_, and original treatises, of which the essay “On the Intellect” and another “On the five essences” are the most noteworthy (Latin tr. by A. Nagy in Baeumker and Hertling’s _Beiträge zur Geschichte der Philosophie des MA._ II. 5. Münster, 1897).