Byzantine prime minister, negotiator for Emperor Andronicus II Palaeologus, and one of the principal literary and philosophical scholars of the 14th century.

The son of George Metochites, a prominent Eastern Orthodox cleric under Emperor Michael VIII Palaeologus and a leading advocate of union with the Latin church, Theodore became a favourite of Emperor Andronicus II and undertook various diplomatic missions to enlist help against the encroaching Ottoman Turks. In a vain attempt to reverse Byzantium's military and political decline through an alliance with Serbia, Metochites, in 1298, led an embassy to the Serbian court at Skoplje and arranged the marriage of Andronicus's five-year-old daughter, Simonis, to Tsar Milutin. As a result, Serbia, although militarily stronger than Byzantium and acknowledged as ruler of formerly Byzantine Macedonia, admitted the universal sovereignty of the Eastern emperor. In his Presbeutikos (“Embassy Papers”), Metochites left a valuable historical account of these negotiations as well as a concrete description of Byzantine influence on Slavic royalty.

Promoted to megas logothetes (“grand logothete,” or “chancellor”), Metochites married Irene Palaeologus and, as a relative of the ruling dynasty, directed Byzantine political affairs from 1321 to 1328, when Andronicus fell from power. Because of his fidelity to Andronicus II, he was deprived of his wealth and exiled by Andronicus III. In 1331 he retired to the Chora Monastery (now Kariye Museum), in Constantinople, to continue his scholarly pursuits. He directed the material and artistic restoration of the monastery, the mosaic work of which, particularly the extant piece showing him offering the church of Chora to an enthroned Christ, represents the acme of 14th-century Byzantine mosaic art.

Metochites' voluminous writings range from scientific to theological matters. His best-known work, Hypomnematismoi kai semeioseis gnomikai (“Personal Comments and Annotations”), commonly designated the “Philosophical and Historical Miscellany,” is an encyclopaedic collection of tracts and essays on classical thought, history, and literature, comprising more than 80 Greek authors. Other treatises on physics, astronomy, physiology, and Aristotelian psychology survive only in Latin translations. His commentaries on the Dialogues of Plato were an important influence on the 15th-century Platonic renaissance.