Averroës was the last great Muslim thinker, summing up and carrying to its conclusions the thought of four hundred years. The philosophy of Islam, which flourished first in the East, in Basra and Bagdad (800-1100), and then in the West, Cordova, Toledo, etc. (1100-1200), was a mixture of Aristotelianism and Neo-Platonism, borrowed, under the earlier Persianizing Khalifs, from the Christian (mainly Nestorian) monks of Syria and Mesopotamia, being consequently a naturalistic system. In it God was acknowledged only as the supreme abstraction; while eternal matter, law, and impersonal intelligence played the principal part. It was necessarily irreconcilable with Muslim orthodoxy, in which a crudely conceived, intensely personal God is all in all. While Persian influence was potent, philosophy flourished, produced some really great scholars and thinkers, made considerable headway against Muslim fatalism and predestination, and seemed in a fair way to bring about a free and rational civilization, eminent in science and art. But no sooner did the fanatical or scholastic element get the upper hand than philosophy vanished, and with it all hope of a great Muslim civilization in the East. This change was marked by Al-Ghazzali, and his book 'The Destruction of the Philosophers.' He died in A.D. 1111, and then the works of Al-Farabi, Ibn-Sina, and the "Brothers of Purity," wandered out to the far West, to seek for appreciation among the Muslim, Jews, and Christians of Spain. And for a brief time they found it there, and in the twelfth century found also eloquent expounders at the mosque-schools of Cordova, Toledo, Seville, and Saragossa. Of these the most famous were Ibn Baja, Ibn Tufail, and Ibn Rushd (Averroës). During its progress, Muslim philosophy had gradually been eliminating the Neo-Platonic, mystic element, and returning to pure Aristotelianism. In Averroës, who professed to be merely a commentator on Aristotle, this tendency reached its climax; and though he still regarded the pseudo-Aristotelian works as genuine, and did not entirely escape their influence, he is by far the least mystic of Muslim thinkers. The two fundamental doctrines upon which he always insisted, and which long made his name famous, not to say notorious, the eternity of matter and of the world (involving a denial of the doctrine of creation), and the oneness of the active intellect in all men (involving the mortality of the individual soul and the impossibility of resurrection and judgment), are both of Aristotelian origin. It was no wonder that he came into conflict with the orthodox Muslim; for in the warfare between Arab prophetism, with its shallow apologetic scholasticism, and Greek philosophy, with its earnest endeavor to find truth, and its belief in reason as the sole revealer thereof, he unhesitatingly took the side of the latter. He held that man is made to discover truth, and that the serious study of God and his works is the noblest form of worship.