But he left Manichaeism, under the influence of astronomy. Astronomy showed him the perfect motion of the stars, i. e., the fundamental elements in the structure of the universe. This made a dualistic principle almost impossible. If the structure of the universe is a structure of regular mathematical forms which can be calculated and which are harmonius, where can you find the effect of the demonic creation in the world? The world as created in its basic structure is good – this is what he derived from it. This means he uses the Greek Pythagorean idea of the cosmos. He used the principle of form and harmony as it was expressed in mathematics.