and orator (Διάχονος καὶ Ρήτωρ ) of Constantinople, was a deacon of the great church (St. Sophia) in that city about the end of the 9th century. He wrote Λόγος εἰς τὸν βίον τοῦ ἐν ἁγίοις πατρὸς ἡμῶν Ι᾿ωσήφ, τοῦ ὑμνγράφου (Vita S. Josephi Hymnographi), published in the Acta Sanctorum (April 3), vol. 1, a Latin version being given in the body of the work, with a learned Commentarius Proevius at p. 266, etc., and the original in the Appendix, p. 34. Allatius (De Psellis, c. 30) cites another work of this writer, entitled Τίς ὁ σκοπὸς τῷ θεῷ τῆς πρώτης τοῦ ἀνθρώπου πλάσεως . κ . τ . λ . (Quid est Consilium Dei in prima Hominis formatione, etc.). The designation JOANNES DIACONUS is common to several medieval writers, as John Galenus or Pediasmus; John Hypatius John, deacon of Rome; and, John Diaconus, a contemporary and correspondent of George of Trebizond. See Acta Sanctorum, 1. c.; Fabricius, Biblica Groeca, 10, 264, 11, 654; Cave, Hist. Lit. 2, Dissertatio 1, 11; Oudin, De Scriptoribus et Scriptis Ecclesiasticis, 2, 335. — Smith, Dict. Greek and Roman Biog. 2, 594.