 Michael Psellos (1018–1078) was one of the most erudite and intriguing figures of the Byzantine Middle Ages. He was given the title “Consul of the Philosophers” and taught all branches of philosophy. He commented on and paraphrased treatises from the Aristotelian Organon (De interpretatione, Prior Analytics), and wrote a large number of short treatises discussing particular philosophical issues raised, in part at least, by his pupils: e.g., on the distinction between homonyms and synonyms, on the characteristic of substance as self-existent (authuparktos), on the Platonic forms, on the unity of the soul and the body, on the problem of evil, on dreams. He also compiled the De omnifaria doctrina, a short encyclopedia in which various philosophical notions are explained in close dependence on Christian as well as pagan authors. His speeches are famous as examples of rhetorical style; there is also a collection of about five hundred of his letters. Although the amount of attention he paid to Aristotle’s works was significant, there is no doubt that Psellos had a strong preference for Plato and the Neoplatonists. On this account he has often — and not unreasonably — been identified as a pivotal figure in the transmission of the Platonic heritage through the Middle Ages. His works show that he carefully read Plotinus, Porphyry, Iamblichus, and especially Proclus, whom he considered as an authority among ancient authors. In particular, he found in the Elements of Theology an elaborate metaphysical system open to adaptation to Christian theology. For although the Christian Trinity differed significantly from the Neoplatonic first principle, Psellos found that Proclus’ view of the general structure of reality, descending from the first cause to intellect, soul nature, body, and matter, could be adopted with some modifications. However, in his attempts to advance philosophical learning, he was often attacked concerning his theological orthodoxy, with the result that he often had to be careful to distance himself from heretical doctrines, e.g., in his writings on the Chaldaean Oracles.