For other persons with the same name ,see Theagenes (disambiguation)
Theagenes was a historical writer, of uncertain date. Stephanus of Byzantium frequently quotes from a work of his, entitled Macedonica (s. v. Altus (Mygdonia) ), as also from another entitled Carica. It is, perhaps, the same Theagenes, who wrote a work on Aegina, quoted by John Tzetzes.
References
Theagenes (historian) Wikipedia(Text) CC BY-SA