In time, however, a consciousness of the vital hostility of his doctrine to current creeds, and of the danger he consequently ran, made him, like so many of his later disciples, anxious to preserve priestly favour. As regards religion he was more complaisant than Abubacer, pronouncing Mohammedanism the most perfect of all popular systems, [1160] and preaching a patriotic conformity on that score to philosophic students. From him derives the formula of a two-fold truth--one truth for science or philosophy, and another for religion--which played so large a part in the academic life of Christendom for centuries. [1161] In two of his treatises, On the harmony of religion with philosophy and On the demonstration of religious dogmas, he even takes up a conservative attitude, proclaiming that the wise man never utters a word against the established creed, and going so far as to say that the freethinker who attacks it, inasmuch as he undermines popular virtue, deserves death. [1162] Even in rebutting, as entirely absurd, the doctrine of the creation of the world, and ascribing its currency to the stupefying power of habit, he takes occasion to remark piously that those whose religion has no better basis than faith are frequently seen, on taking up scientific studies, to become utter zendeks. [1163] But he lived in an age of declining culture and reviving fanaticism; and all his conformities could not save him from proscription, at the hands of a Khalif who had long favoured him, for the offence of cultivating Greek antiquity to the prejudice of Islam. All study of Greek philosophy was proscribed at the same time, and all books found on the subject were destroyed. [1164] Disgraced and banished from court, Averroës died at Morocco in 1198; other philosophers were similarly persecuted; [1165] and soon afterwards the Moorish rule in Spain came to an end in the odour of sanctity. [1166] So complete was now the defeat of the intellectual life in Western Islam that the ablest writer produced by the Arab race in the period of the Renaissance, Ibn Khaldun of Tunis (1332-1406), writes as a bigoted believer in revelation, though his writings on the science of history were the most philosophic since the classic period, being out of all comparison superior to those of the Christian chroniclers of his age. [1167] So rationalistic, indeed, is his method, relatively to his time, that it is permissible to suspect him of seeking to propitiate the bigots. [1168] But neither they nor his race in general could learn the sociological lessons he had it in him to teach. Their development was arrested for that period. § 6