GEMISTUS PLETHO [or Plethon], GEORGIUS (c.1355-1450), Greek Platonic philosopher and scholar, one of the chief pioneers of the revival of learning in Western Europe, was a Byzantine by birth who settled at Mistra in the Peloponnese, the site of ancient Sparta. He changed his name from Gemistus to the equivalent Pletho ("the full"), perhaps owing to the similarity of sound between that name and that of his master Plato. He invented a religious system founded on the speculative mysticism of the Neoplatonists, and founded a sect, the members of which believed that the new creed would supersede all existing forms of belief. But he is chiefly memorable for having introduced Plato to the Western world. This took place upon his visit to Florence in 1439, as one of the deputies from Constantinople on occasion of the general council. Cardinal Bessarion became his disciple; he produced a great impression upon Cosimo de' Medici; and though not himself making any very important contribution to the study of Plato, he effectually shook the exclusive domination which Aristotle had exercised over European thought for eight centuries. He promoted the union of the Greek and Latin Churches as far as possible, but his efforts in this direction bore no permanent fruit. He probably died before the capture of Constantinople. The most important of his published works are treatises on the distinction between Plato and Aristotle as philosophers (published at Venice in 1540); on the religion of Zoroaster (Paris, 1538); on the condition of the Peloponnese (ed. A. Ellissen in Analekten der mittel- und neugriechischen Literatur, iv.); and the (ed. C. Alexandre, Paris, 1858). In addition to these he compiled several volumes of excerpts from ancient authors, and wrote a number of works on geography, music and other subjects, many of which still exist in MS. in various European libraries.
See especially F. Schultze, Geschichte der Philosophie der Renaissance, i. (1874); also J.A. Symonds, The Renaissance in Italy (1877), ii. p. 198; H.F. Tozer, "A Byzantine Reformer," in Journal of Hellenic Studies, vii. (1886), chiefly on Pletho's scheme of political and social reform for the Peloponnese, as set forth in the pamphlets addressed to Manuel II. Palaeologus and his son Theodore, despot of the Morea; W. Gass, Gennadius und Pletho (1844). Most of Pletho's works will be found in J.P. Migne, Patrologia Graeca, clx.; for a complete list see Fabricius, Bibliotheca Graeca (ed. Harles), xii.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)