Delcus, a titular see of Thrace, suffragan of Philippopolis. The Greek name of the place was Delkos or Delkoi, later Derkos or Derkoi; the latter forms have prevailed. The Turkish and common name is Derkos. It is now a little village southwest of Kara Bournou, a promontory on the Black Sea, and on the southern bank of Lake Derkos, the waters of which are brought to Constantinople by an aqueduct. There are about 300 inhabitants. The see, though some have connected its origin with the preaching of St. Andrew, is not mentioned before the eighth century; however a rather obscure record of Balsamon (P.G., CXXXVII, 548) permits the supposition that it was established shortly after the Trullan Council of 692. The first known bishop is Gregory, who attended the Second Council of Nica in 787. In the records of the councils under Photius are found the signatures of his partisan Neophytus and of Macarius, the partisan of St. Ignatius. About 840 the see stood twentieth among the autocephalous archbishoprics. Its archbishop, John, subscribed a synodal sentence in 997. Balsamon (P.G., CXXXVIII, 273) speaks of another prelate who sought permission to reside in the larger and richer city of Phileas. Another was reproached in the Holy Synod by the Patriarch Michael with having ordained a bishop native of Constantinople and before the canonical age (ibid., 213); he was perhaps the John who was present in 1166 at the council of Constantinople, known as “Pater major me est”. One Gregory subscribed another council in 1193. In 1316 the see was given to the Archbishop of Nymphieum, who had been deprived of his own (Miklosich and Miller, “Acta et diplomata graeca”, I, 50). Luke was archbishop in 1329 (ibid., 98). In 1356 the see was per adjunctionem in the hands of the Metropolitan of Bizye (ibid., 355). In 1365 it had again an occupant, and its bishop in 1379 and 1381 was Paul; in 1389 Joseph was bishop (op. cit., II, 6, 39, and 129). In 1466 it was and probably had long been ruled directly by the Patriarch of Constantinople [Kambouroglous, Monuments for History of Athens (Gr.), II, 354]. It was not reestablished until the beginning of the seventeenth century, when the titular resided at Therapia on the Bosphorus. Delcus was made a metropolis in 1655. In October, 1746, it was raised to the eighth rank of the Greek hierarchy (Mansi, Col. concil., XXXVIII, 527). The diocese now includes 41 villages in the vicinity of Constantinople and along the shores of the Black Sea and the Sea of Marmora, among them San Stefano, Makri-Keui, and Beuyuk-Dore, with Catholic parishes conducted by Capuchins, Dominicans, and Minor Conventuals.