Such ideas could not be acceptable to the Ulemas, who saw the absolute authority in religious matters slipping from their hands. Only a moderate power of perception was needed to understand what dangers for the official hierarchy lurked in the ideas of these enthusiasts who claimed to derive divine wisdom from a source so different to that of which the Ulemas believed themselves to be the sole dispensers. It is true that Arab mysticism had never taken such a bold flight as Persian theosophy, which proclaimed openly a Pantheistic system, in which the authority of the books revealed to different prophets was displaced by a poetic belief. According to this faith, the universe was an emanation of God, the human soul a spark of the Divine Essence gone astray in this transitory world, but destined to return finally to God, after having been purified of its earthly stains. The Arab Sufis did not go so far; for them the Koran was always the Word of God, and Muhammed was His prophet. They conformed externally to the precepts of Islam, but claimed at the same time to understand God and His law better than the theologians, and that not by the study of large volumes of exegesis and traditions, but by celestial inspiration. The orthodox mullahs understood the danger, and did not conceal their growing irritation against these audacious heretics. The government and the great majority of Moslems were on the side of the Ulema, but the mystics found sympathy among the people, and their ideas spread with incredible rapidity. In the eleventh century, a man of great ability, of whom the Muhammadans are justly proud, made a vigorous effort to reconcile orthodox Islam with the Sufi doctrines current in his time. This man was Ghazzali. He consecrated the labour of a lifetime to this task, and his chief work, "The Revival of the Religious Sciences," is a veritable encyclopaedia of Islam. He did not work in vain, but succeeded in erecting a system in which dogmatic theology is cleverly combined with the theosophy of the Arab school of mysticism. But Islam such as Ghazzali conceived it is no longer that of ancient times. Another order of ideas has been insensibly substituted for the austere creed of the Prophet of Mecca, the very foundations of which they have undermined. Muhammad's religious edifice remains standing, its framework and external outlines are the same; but the spirit which informs it is profoundly different. Arab mysticism has succeeded in finding a footing in the official circles of the Moslem hierarchy.