The paper deals with the reception of Aristotle’s definition of rhetoric(Rhet. I 1355b26–27) in several Byzantine commentators of Hermogenes’and Aphthonius’ treatises. A justification of critical interpretationof this definition is to be found in the commentaries of Troilus and Athanasius(4th/5th century) as well as Sopatros (6th century) and Doxapatres(11th century), Maximus Planudes (13th/14th century) and several anonymouscommentators. The Byzantine tradition has found Aristotle’s definitionof rhetoric to be all too theoretical and insufficiently connected topractical activity, which Byzantium identified with political life.