It is true that more than one of his contemporaries accused him of hypocrisy, saying that he had an esoteric doctrine for himself and his private circle of friends, and an exoteric for the vulgar. His Sufistic leanings might lend some colour to this accusation, it being a well-known Sufi habit to cloak their teaching under a metaphorical veil, wine representing the love of God, etc., as in Hafiz and Omar Khayyam. Against this must be set the fact that in his autobiography written near the close of his life, he constantly refers to his former works, which he would hardly have done had he been conscious of any striking discrepancy between his earlier and his later teaching. There is no reason to doubt his previously-quoted statement that he "studied philosophy in order to refute the philosophers." He was, at any rate, intensely indignant at having his orthodoxy impugned, as appears from a striking story narrated by the Arabic historian Abu'l Feda. He tells us that Ghazzali's most important work, "The revival of the religious sciences" had created a great sensation when it reached Cordova. The Muhammadan theologians of Spain were rigidly orthodox, and accused the work of being tainted by heresy. They represented to the Caliph Ali Ibn Yusuf that not only this but all Ghazzali's other works which circulated in Andalusia should be collected and burnt, which was accordingly done. Not long after, a young Berber from North Africa named Ibn Tumart wandered to Bagdad, where he attended Ghazzali's lectures. Ghazzali noticing the foreigner, accosted him, and inquired regarding religious affairs in the West, and how his works had been received there. To his horror he learned that they had been condemned as heretical and committed to the flames by order of the Almoravide Caliph Ali. Upon this, Ghazzali, raising his hands towards heaven, exclaimed in a voice shaken with emotion, "O God, destroy his kingdom as he has destroyed my books, and take all power from him." Ibn Tumart, in sympathy with his teacher, said, "O Imam[44] Ghazzali, pray that thy wish may be accomplished by my means." And so it happened. Ibn Tumart returned to his North African, proclaimed himself a Mahdi, gained a large following among the Berbers, and overthrew Ali and the dynasty of the Almoravides. This story is not entirely beyond doubt, but shows the importance attached by Ghazzali's contemporaries to his influence and teaching.