 Illus served Zeno well, defeating the usurper Marcian, but came into conflict with the dowager Empress Verina, and supported the revolt of Leontius, but the rebellion failed and Illus was killed.Illus was an Isaurian, but the time and place of his birth are unknown; he had a brother, called Appallius Illus Trocundus.Illus is said to have held various offices under the Emperor Leo I (457—474), and to have been an intimate friend of Zeno, apparently before his accession.