Proclus, a Greek philosopher of the Neo-Platonic school, born in Constantinople in A. D. 412, died in Athens in 485. In his childhood he lived at Xanthus in Lycia, afterward for several years in Alexandria, studying under the most eminent teachers, and before he was 20 years old removed to Athens. On the death of Syrianus he succeeded him in the school at Athens, and hence is sometimes called Diadochus (the successor). He adopted the ascetic system which became common in the later Neo-Platonic school, abstained almost entirely from animal food, refused to marry, spent his money freely in acts of benevolence, and observed numerous fasts and vigils. He worshipped the sun and moon, the spirits of heroes and philosophers, and even the spirits of the whole human race, and celebrated all important religious festivals, no matter of what nation. In addition to his religious exercises, he delivered five lectures a day. He was distinguished as a mathematician and grammarian. His extant works consist chiefly of commentaries, principally on Plato. One of his original works is entitled "Twenty-two Arguments against the Christians," in which he endeavored to maintain the eternity of the universe.

As a writer he is usually regarded as one of the clearest of his school, but as a philosopher his reputation has never stood high. There is no complete edition of his extant productions; the best is by Cousin (6 vols. 8vo, Paris, 1820-'27). Translations of several of his works have been made into English by Thomas Taylor.