The elements of the situation remained fundamentally unchanged; and when the Moorish military power began to feel more and more the pressure of the strengthening Christian foe, it lay in the nature of the case that the fanatical species should predominate. The rationalistic and indifferent types would figure as the enemies of their race, very much as such types would have done in Covenanting Scotland. At length, in the eleventh century, the weakened Moorish princes had to call in the aid of the fanatical Almoravides from Barbary; and these, with the full support of the priesthood and the pious, established themselves at the head of affairs, reducing everything as far as possible to the standards of the eighth century.[391] And when the new barbarism in time grew corrupt, as that of the Goths and Vandals had done in earlier ages, the "Unitarian" Almohades in turn (twelfth century) overthrew the Almoravides in Spain as they had already done in Africa, only to be themselves overthrown a hundred years later by the Christians. Thereafter the curtailed Moorish power, pent up in Southern Spain, reverted to the spirit of fanaticism which national failure generates in religious minds; and from the thirteenth century to the final overthrow at the end of the fifteenth the intellectual life of Saracen Spain was but a long stagnation. A civilisation driven back on superstition and fanaticism[392] thus gave way to a revived barbarism, which itself, after a few centuries of power, was arrested in its progress by the same order of forces, and has ever since remained in the rear of European development. A remarkable exception, indeed, is to be noted in the case of Ibn Khaldun (1332-1406), who in the narrow world of Tunis attained to a grasp of the science of history such as no Christian historian up to his time had remotely approached.[393] Such an intellectual phenomenon sufficiently disposes of the current formulas about the innate incapacities of "the Semitic mind." But whether it were that he dared not say what he thought of the fatal influence of the Sacred Book, or that on that side he was really, as he is ostensibly, quite uncritical, Khaldun fails, in his telling survey of Arab decadence, to set forth the decisive condition of intellectual arrest; and his luminous impeachment of the civilisation of his race failed to enlighten it. In Persia the same forces wrought closely similar results. The Greek stimulus, after working wonders in science and rational thought, failed to sustain a society that could not politically evolve beyond despotism; and economic evil and intellectual decay together undermined the empire of the Caliphs,[394] till the Turks could overrun it as the Christians did Moorish Spain; they themselves, however, adding no new culture developments, because under them no new culture contacts were possible.