the House of Wisdom (_Baytu ’l-Ḥikma_) at Baghdád, an institution which comprised a well-stocked library and an astronomical observatory. Among the celebrated translators of the ninth century, who were themselves conspicuous workers in the new field, we can only mention the Christians Qusṭá b. Lúqá and Ḥunayn b. Isḥáq, and the Ṣábian Thábit b. Qurra. It does not fall within the scope of this volume to consider in detail the achievements of the Moslems in science and philosophy. That in some departments they made valuable additions to existing knowledge must certainly be granted, but these discoveries count for little in comparison with the debt which we owe to the Arabs as pioneers of learning and bringers of light to mediæval Europe.[679] Meanwhile it is only possible to enumerate a few of the most eminent philosophers and scientific men who lived during the ‘Abbásid age. The reader will observe that with rare exceptions they were of foreign origin. The leading spirits in philosophy were:-- [Sidenote: Kindí.] 1. Ya‘qúb b. Isḥáq al-Kindí, a descendant of the princely family of Kinda (see p. 42). He was distinguished by his contemporaries with the title _Faylasúfu ’l-‘Arab_, 'The Philosopher of the Arabs.' He flourished in the first half of the ninth century. [Sidenote: Fárábí.] 2. Abú Naṣr al-Fárábí († 950 A.D.), of Turkish race, a native of Fáráb in Transoxania. The later years of his life were passed at Aleppo under the patronage of Sayfu ’l-Dawla. He devoted himself to the study of Aristotle, whom Moslems agree with Dante in regarding as "il maestro di color che sanno." [Sidenote: Ibn Síná.] 3. Abú ‘Alí Ibn Síná (Avicenna), born of Persian parents at Kharmaythan, near Bukhárá, in the year 980 A.D. As a youth he displayed extraordinary talents, so that "in the sixteenth year of his age physicians of the highest eminence came to read medicine with him and to learn those modes of treatment which he had discovered by his practice."[680] He was no quiet student, like Fárábí, but a pleasure-loving, adventurous man of the world who travelled from court to court, now in favour, now in disgrace, and always writing indefatigably. His system of philosophy, in which Aristotelian and Neo-platonic theories are combined with Persian mysticism, was well suited to the popular taste, and in the East it still reigns supreme. His chief works are the _Shifá_ (Remedy) on physics, metaphysics, &c., and a great medical encyclopædia entitled the _Qánún_ (Canon). Avicenna died in 1037 A.D. 4. The Spanish philosophers, Ibn Bájja (Avempace), Ibn Ṭufayl, and Ibn Rushd (Averroes), all of whom flourished in the twelfth century after Christ. [Sidenote: Medicine, Astronomy, and Mathematics.] [Sidenote: Bírúní 973-1048 A.D.]