During the period between Augustine and Aquinas, however, science almost died out in Europe, and leadership in philosophy went into the hands of the Arabs. Between 813 and 833 the works of Aristotle were translated into Arabic, and they form the basis of the natural philosophies of the Arabians. Avicenna (980-1037) probably held a naturalistic theory of evolution, and is known to have been fundamentally modern in his conceptions of geology. During the tenth century scientific books were imported into Spain in considerable numbers, and the Spanish scientific movement culminated in the works of Avempace and Abubacer (Abn-Badja and Ibn-Tophail). The former held that there were strong relationships between men, animals, plants, and minerals, which made them into a closely united whole. Abubacer, a poet, believed in the spontaneous generation of life, and sketched in a highly imaginative fashion the development of human thought and civilization. But the reactionary trend of church thought during the dark ages finally attacked and conquered Arabic progress. In 1209 the Church Provincial Council of Paris forbade the study of Arabic writers, and even declared against the reading of Aristotle’s “Natural Philosophy.” During the middle ages the progress backward was carried to an even greater degree. Men no longer cared to think, or to discover things; they preferred to be told what they should believe. This attitude was encouraged by the authorities of the church, who represented power, and who depended for their easy existence upon the servility of the people at large. Obedience to authority in intellectual as well as in political affairs was demanded of everyone, and by almost everyone was rendered as a matter of course. Those who by chance made real discoveries, and found that they contradicted the established authorities, either refused to believe their own senses, or else feared to publish their information because of the almost certain prosecution that would follow. To believe blindly, without analysis or question, was considered right and proper; to seek knowledge for oneself was a crime that the medieval church, and her governmental allies, stood ever ready to punish.