Prochoros Kydones (c. 1333 Thessaloniki to c. 1370 Constantinople), (also spelled Prochorus Cydones), is a key figure in the spiritual and intellectual history of Byzantium in the fourteenth century. It was to a great extent due to him and his brother Demetrios Kydones that Thomism spread to the Christian East. Translating main works of Thomas Aquinas and becoming proponents of his ideas, the two brothers stimulated intense theological controversy, in the course ofwhich Byzantine thought contended its identity against western Scholasticism. Prochoros is by no means an original thinker. His significance lies in the fact that he applies the concepts and principles of Tho-mistic philosophy to the context of the Palamite controversy. He opposed the Christian Aristotelianism of Thomas Aquinas and the Scholastic method of distinctions to the Neoplatonic aspects of Palamas’ thought. Following Thomas Aquinas, Prochoros identifies Being, Essence, and Energies in God. Thus, the Divine energies do not constitute anything different from the Divine essence. From this point of view Palamas is ambiguous claiming both the non-hypostatic nature of the energies and their particular ontological status between God and creation; emanating from the essence, they constitute the Divine Wisdom (Intellect), which is Divine but not God, and is also non-created. Opposing these trends of thought, Prochoros formulated a conception of logic and rational discourse, which was unacceptable for Palamite theology.