Ibn Rushd (Averroës), the contemporary of Maimonides, closed the first great philosophical era of the Muslims. He was a defender of Aristotelian philosophy against Ash'ari theologians led by Al-Ghazali. Averroes' philosophy was considered controversial in Muslim circles. The theories of Ibn Rushd do not differ fundamentally from those of Ibn Bajjah and Ibn Tufail, who only follow the teachings of Ibn Sina (Avicenna) and Al-Farabi. Like all Islamic Peripatetics, Ibn Rushd admits the hypothesis of the intelligence of the spheres and the hypothesis of universal emanation, through which motion is communicated from place to place to all parts of the universe as far as the supreme world—hypotheses which, in the mind of the Arabic philosophers, did away with the dualism involved in Aristotle's doctrine of pure energy and eternal matter. His ideas on the separation of philosophy and religion, further developed by the Averroist school of philosophy, were later influential in the development of modern secularism.