Theophylact Simocatta
John wrote a history of the Byzantine-Persian wars; from the campaigns of Khosrau I against Justin II, to the flight of his grandson Khosrau II to the Byzantines. The work is lost, but a fragment is preserved. The history was used by Evagrius and Theophylact Simocatta. As with many other Byzantine works, it is written in an archaic form of Greek, meant to imitate the classical style (e.g. Thucidydes).