Simeon Seth(i) or Symeon Seth(i) (Greek: Συμεὼν Μάγιστρος Ἀντιοχείας τοῦ Σήθι, "Symeōn Magister of Antioch, son of Sēth", sometimes also "Simeo" and "Sethus") was an 11th-century Jewish Byzantine doctor, scholar, and grand Chamberlain (protovestiarius) under Emperor Michael VII Doukas, originally from Antioch. He was a contemporary of Michael Psellos.
He revised Psellos's Σύνταγμα κατὰ στοιχείων περὶ τροφῶν δυνάμεων (TLG no. 3113.002; in Latin the Syntagma de alimentorum facultatibus or De cibarium facultate, "On the Properties of Foods"), which criticizes Galen and emphasizes eastern medical traditions. Paul Moore says "the text is really an explanation of Aetius Amidenus Iatricorum libri xvi, with material drawn from Dioscorides Liber de alimentis. Apparently, Psellos wrote the work for the emperor Constantine IX Monomachos. It was then revised for Michael VII Doukas by Symeon Seth, who wrote a brief introduction (the proem.), made some corrections in the text, omitting some chapters. The work deals with some two hundred and twenty-eight plants and animals." The Syntagma is an important source for Byzantine cuisine and dietetics.
Simeon's work Σύνοψις τῶν φυσικῶν (Conspectus rerum naturalium, "On the things of nature": TLG 3113.003) is a treatise on the natural sciences divided into five books. The first concerns the earth; the second, the elements; the third, the sky and the stars; the fourth, matter, form, nature and the soul (sense perception); the fifth, the final cause and divine providence. The work is heavily influenced by the philosophy of Aristotle.
He learned astronomy from Arabic sources and translated the book of fables Kalilag and Damnag from Arabic to Greek in about 1080. The protagonists in the Greek version are named "Stephanites" and "Ichnelates" (TLG 3113.001).