After centuries of being unknown, the philosophy of Aristotle came to Western European universities with the force of a scientific revolution. The secular, scientific doctrines of Aristotle provided a great challenge to theologians and philosophers. Some regarded the new thought as a threat, but Aquinas welcomed Aristotelian philosophy and used it to further in extraordinary ways his own philosophy and theology. Aquinas took Aristotle farther than a Greek philosopher alone could have gone, but he was also critical of Aristotle's limitations.