Born in Constantinople about 1355, died in the Peloponnesus, 1450. Out of veneration for Plato he changed his name from Gemistos to Plethon. Although he wrote commentaries on Aristotle's logical treatises and on Porphyry's "Isagoge", he was a professed Platonist in philosophy. Owing, most probably, to the influence of Mohammedan teachers, he combined with Platonism, or rather with Neo-Platonism, the most extraordinary kind of Oriental mysticism and magic which he designated as Zoroastrianism. It was due, no doubt, to these tendencies of thought that he openly abandoned Christianity and sought to substitute paganism for it as a standard of life. When he was about fifteen years old he visited Western Europe in the train of the Emperor John Palaeologus. After his return to Greece, he settled at Misithra in the Peloponnesus, the site of ancient Sparta, and there he spent the greater part of his life. In 1438, although he was then in his eighty-third year, he again accompanied the Emperor to Italy, where he was designated as one of the six champions of the Orthodox Church in the Council of Florence. His interest in ecclesiastical matters was, however, very slight. Instead of attending the Council, he spent his time discoursing on Platonism and Zoroastrianism to the Florentines. It was his enthusiasm for Platonism that influenced Cosimo de Medici to found a Platonic Academy at Florence. In 1441 Plethon had returned to the Peloponnesus, and there he died and was buried at Misithra in 1450. In 1465 his remains were carried to Rimini and placed in the church of St. Francis, where an inscription, curiously enough, styles him "Themistius Byzantinus". Among his disciples was the learned Cardinal Bessarion. Plethon's most important works are the "Laws" written in imitation of Plato's "Laws", which was condemned by Gennadios, Patriarch of Constantinople, and "On the Differences between Plato and Aristotle", in which he attacks the Aristotelian philosophy and asserts the superiority of Platonism. He also composed a work in defence of the Greek doctrine of the Procession of the Holy Ghost. In his philosophical system he borrows largely from the Neo-Platonist, Proclus, and mingles with the traditional Neo-Platonic mysticism many popular Oriental superstitions. His influence was chiefly negative. His attack on Aristotelianism was to some extent effective, although opposed to him were men of equal ability and power, such as Gennadios, Patriarch of Constantinople. He was honoured by the Italian Platonists as the restorer of the Academy, and as a martyr for the cause of Platonism.

The Laws, written about 1440, was printed at Paris, 1541 and (in Latin tr.) at Basle, 1574. The comparison of Plato and Aristotle was also printed at Basle, 1574. MIGNE, P. G., CLX, 773 sqq., reprints these and other Greek works of Plethon, with Latin tr. The best work on Plethon is a dissertation by FRITZ SCHULTZE, Georgios Gemistos Plethon (Jena, 1871). See also SANDYS, Hist. of Classical Scholarship, II (London, 1908), 60; SYMONDS, Renaiss. in Italy, Pt. ii (New York, 1888), 198 sqq.; CREIGETON, Hist. of Papacy, IV (London, 1901), 41-46.

WILLIAM TURNER.