Proclus (prōˈkləs) [key], 410?–485, Neoplatonic philosopher, b. Constantinople. He studied at Alexandria and at Athens, where he was a pupil of the Platonist Syrianus, whom he succeeded as a teacher. As a partisan of paganism he was forced to leave Athens, but he returned at the end of a year. A synthesizer of Neoplatonic doctrines, Proclus gave the philosophy its most systematic form. He kept the elements of Plotinus, but introduced a principle of triadic development in the series of emanations; the three stages are an original, an emergence from the original, and a return in a lower form to the original. Proclus differed from Plotinus in regard to the origin of matter, which he held to emerge from the first emanation rather than from the plastic forces. Among his writings are commentaries on several Platonic dialogues and two treatises, On Plato's Theology and Institutes of Theology. See Neoplatonism.
See Fragments of the Lost Writings of Proclus (ed. by R. Navon, tr. by T. Taylor, 1987).