Iamblichus was once considered one of the great philosophers. The Emperor Julian followed Iamblichus's teachings to guide the restoration of traditional pagan cults in his campaign against Christianity. Although Julian was unsuccessful, Iamblichus's ideas persisted well into the Middle Ages and beyond. His vision of a hierarchical cosmos united by divine ritual became the dominant worldview for the entire medieval world. Even Ralph Waldo Emerson wrote that he expected a reading of Iamblichus to cause a "revival in the churches." But modern scholars have dismissed him, seeing theurgy as ritual magic or "manipulation of the gods." Shaw, however, shows that theurgy was a subtle and intellectually sophisticated attempt to apply Platonic and Pythagorean teachings to the full expression of human existence in the material world.