George Gemistos (Constantinople 1360- Mystras 1452) was one of the most outstanding personalities of the Late Byzantine period. The son of a prominent family, he was born in Constantinople in 1360 and acquired a very good general and classical education. In 1380 he travelled to Adrianople which was then the capital of the Ottoman state (Ottomans had already invaded and occupied most of the greek lands). There, he studied with a mysterious Jew, Helisseus, who seems to have been an adherent of Zoroastrianism.

When he returned home, he went on to Mistra, a rich greek city near ancient Sparta. There he embarked on a long career as a teacher, judge, philosopher and writer and eventually became the most highly esteemed scholar in the city. He taught philosophy at the court of the despotai of Mistra and accompanied the emperor John VIII Palaiologos and Patriarch Joseph to the Council of Ferrara-Florence.

During his stay in Florence he persuaded Cosimo de Medici to found a Platonic Academy. Gemistos was a fanatical supporter of platonic philosophy, so much so that he changed his name to "Plethon" so that it would be reminiscent of "Plato". Among his many notable works are philosophical treatises, memoranda on the political situation of the despotate of the Morea (Peloponnese), works on astrology and geography, all of which are imbued by a classical spirit. The picture that shines through his writings is that of a patriot and a thinker, but also that of a politician and a social reformer. As a follower of Platonism Plethon influenced the Western scholastic philosophy and the spirit of the Renaissance and humanism, and also dared to criticise and question the Christian dogma as a whole.

Plethon used to remind to the emperor that "Our language and culture bear witness that we are Greeks". He urged him to protect Peloponnese and to organize her defense system and her agriculture, because from this place started Hellenism to spread all over the world and from this place should again Hellenes propagate their culture. He accused the monks of not offering anything to the society and all their care was getting rich.

His writings aroused the strong opposition of the Church. His book Nomon Syngraphe,("Book of Laws") presents the religious, political and social reforms he advocated to the despots of Morea. Through his writings he promoted the nationalization of land, introduced the notion of common origin and advocated a state-controlled economy. His exceptional intellectual activity and chiefly his contribution to philosophical thought established him as one of the most important personalities in Byzantium. So great was the admiration of the Italians for the Greek philosopher that in 1465 his remains were brought to the Saint Francisco Church for burial.