Proclus (412–485) wrote Elements of Theology and Plato’s Theology, which had a lasting effect on subsequent philosophy, particularly that of Hegel (1770–1831) 13 centuries later. He added to the idea of emanations by adding to their downward movements, horizontal movements at different stages of their descent. That resulted in a great multiplication of divine entities, or “henads,” with which Proclus associated Greek deities. He also developed the triadic ruling principle of “remaining-proceeding-returning. That is, the deity remained what it was while its emanations proceeded downward to ordinary existence, and human understanding of this process and communion with the deity constituted returning. Aside from his spiritual work, Proclus wrote on mathematics, astronomy, physics, and literary criticism.