A titular see in Paphlagonia. The ancient name of the town is unknown; it may have been Eupatoria which Pliny (VI, ii, 3), followed by Le Quien and Battandier, wrongly identifies with the Eupatoria of Mithridates. The latter was called Magnopolis by Pompey. Pompeiopolis was, with Andrapa-Neapolis, in 64 B. C. included by Pompey in the Province of Pontus, but the annexation was premature, as the town (which ranked as a metropolis) was restored to vassal princes of eastern Paphlagonia and definitively annexed to the Roman Empire in 6 B. C. Strabo (XIII, iii, 48) says that in the neighbourhood was a mine of realgar or sulphuret of arsenic, which was worked by criminals. As early as the middle of the seventh century the "Ecthesis" of Pseudo-Epiphanius (ed. Gelzer, 535) ranks it as an autocephalous archdiocese, which title it probably received when Justinian (Novellæ, xxix) reorganized the province of Paphlagonia. In the eleventh century Pompeiopolis became a metropolitan see (Parthey, "Hieroclis Synecdemus", 97) and it was still such in the fourteenth century (Gelzer, "Ungedruckte-Texte der Notitiæ episcopatuum", 608). Shortly afterwards the diocese was suppressed. Le Quien (Oriens christ., I, 557-60) mentions fourteen titulars of this diocese the last of whom, Gregory, lived about 1350. Amon them were Philadelphus, at the Council of Nicæa (325); Sophronius, at that of Seleucia; Arginus, at Ephesus (431); Ætherius, at Chalcedon (451); Severus, Constantinople (553); Theodore, Constantinople (680-1); Maurianus, Nicæa (787); and John, Constantinople (869). Pompeiopolis is now called Tach-Keupru (bridge of stone), because of an ancient bridge over the Tatai-Tchai or Gueul-Irmak, the ancient Ammias, and is in the sandjak and vilayet of Kastamouni twenty-five miles north-east of that town. It has about 7000 inhabitants, of whom 700 are Christians, the majority Armenian schismatics.
RAMSAY, Geography of Asia Minor (London, 1890), 192, 318; ANDERSON, Studia Pontica (Brussels, 1903), 93; CUINET, La Turquie d'Asie, IV (Paris, 1894), 484-7.
S. VAILHÉ.