Sergios 57 was possibly the man known from Arab sources as Ibn Qatuna (see below) (but see also Damianos 2).

Sergios 57 was nicknamed Niketiates (Νικητιάτης; i.e. from the village of Niketia near Amastris in Paphlagonia); he was a relation of the empress Theodora (Theodora 2) and was one of the leading figures in the senate (named with Theoktistos 3, Bardas 5 and Petronas 5); he was one of the champions of Orthodoxy (i.e. an iconophile) when the veneration of icons was restored under Theodora 2: Acta Davidis, Symeonis et Georgii 245, 30-246, 2 (Σέργιον τὸν Νικητιάτην, Θεόκτιστον, Βάρδαν καὶ Πετρωνᾶν, ἀνδρὰς ὀρθοδοξοτάτους καὶ τῆς συγκλήτου τυγχάνοντας πρώτους βουλῆς).

A magistros, he founded the monastery of the Theotokos of Niketiates on the Gulf of Nikomedeia: Synax. Eccl. Const. 777ff. (μαγιστροῦ τοῦ συνστησαμένου τὴν μονὴν τῆς ὑπεραγίας Θεοτόκου τὴν ἐπονομαζομένην τοῦ Νικητιάτου, τὴν ἐν τῷ κόλπῳ τῆς Νικομηδείας μεταξὺ τῶν δύο ἐμπορίων Καλοῦ Ἀγροῦ καὶ Δόρκωνος κειμένην). He was given command of a Roman expedition sent against Crete, with the support of the emperor Michael III (Michael 11) and the senate: Synax. Eccl. Const. 777ff. (τοῦ δὲ ῥωμαϊκοῦ στόλου κατελθόντος τῷ τότε χρόνῳ τῇ Κρήτῃ, αὐτὸς ἀπεστάλη παρὰ Μιχαὴλ τοῦ βασιλέως καὶ πάσης τῆς συγκλήτου, μόλις εἰς τοῦτο αὐτὸν πεισάντων, ἐξάρχειν καὶ κυριεύειν πάντος τοῦ στρατοπέδου δι' εὐφυΐαν καὶ τὸ ἱκανὸν εἶναι τῶν ῥωμαϊκῶν ταγμάτων κρατεῖσθαι).

Sergios 57 was perhaps (according to an hypothesis of Grégoire) identical with Ibn Qatuna, one of the leaders of the Roman fleet which defeated the Arabs at Damietta in 853; see Vasiliev, Byzance et les Arabes I, p. 194, for the references to Tabari and Yaqubi, and cf. H. Grégoire, "Etudes sur le neuvième siècle", Byz 8 (1933) pp. 515-550, at 515-534. Cf. also Damianos 2, Bardas 5 and Ooryphas 3.

A native of Paphlagonia, he came from the village of Niketia near Amastris; he was related to the empress Theodora (Theodora 2); he founded the monastery of the Theotokos of Niketiates on the Gulf of Nikomedeia; in the time of the patriarch John Grammatikos (Ioannes 5) and the emperor Theophilos (Theophilos 5) he championed the restoration of the veneration of icons; he led an expedition to Crete, perhaps in 866, and died there; his body was first interred in the monastery of the Magistros (τοῦ Μαγιστροῦ) on Crete, and later was transferred to the monastery which he had founded; he is commemorated on 28 June: Acta Davidis, Symeonis et Georgii 245, 30-246, 2.

Sergios 57 is possibly identical with Sergios 64 and/or Sergios 65. If so, he had the titles magistros, logothetes of the dromos, genikos logothetes, anthypatos, patrikios, and basilikos protospatharios.

See further on this man P. Peeters, "H. Grégoire, Etudes sur le neuvième siècle", Anal. Boll. 52 (1934) pp. 145-147.; Winkelmann, Quellenstudien, pp. 166, 190; Janin, Centres 94.

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