Bithynium or Bithynion (Ancient Greek: Βιθύνιον) was a city in the interior of Bithynia, lying above Tius, as Strabo describes it,[1] and possessing the country around Salone or Salon, which was a good feeding country for cattle, and noted for its cheese.[2] It was the capital of Salone district. Bithynium was the birthplace of Antinous, the favourite of Hadrian, as Pausanius tells us,[3] who adds that Bithynium is beyond, by which he probably means east of, the river Sangarius; and he adds that the remotest ancestors of the Bithynians are Arcadians and Mantineis. In this case a Greek colony settled here. Bithynium was afterwards called Claudiopolis, a name which it is conjectured it first had in the time of Tiberius; but it is strange that Pausanias does not mention this name. Dio Cassius speaks of it under the name of Bithynium and Claudiopolis also.[4] It later bore the name Hadriana after the emperor.[5] The names of Claudiopolis and Hadriana appear on coins minted here.

The town was Christianised early and became an archbishopric. An archbishop suffered martyrdom under Diocletian. No longer a residential see, it remains a titular see of the Roman Catholic Church under the name Claudiopolis in Honoriade.[6] A former titular see under the name of Claudiopolis in Bithynia was suppressed.[7]

Its site is occupied by the modern town of Bolu, Asiatic Turkey.[5][8]


  1. ^ Strabo. Geographica. Vol. p. 565. Page numbers refer to those of Isaac Casaubon's edition.
  2. ^ Pliny. Naturalis Historia. Vol. 11.97.
  3. ^ Pausanias. Description of Greece. Vol. 8.9.1.
  4. ^ Dio Cassius, 69.11. ed. Reimarus, and his note.
  5. ^ a b Richard Talbert, ed. (2000). Barrington Atlas of the Greek and Roman World. Princeton University Press. p. 86, and directory notes accompanying.
  6. ^ Catholic Hierarchy
  7. ^ Catholic Hierarchy
  8. ^ Lund University. Digital Atlas of the Roman Empire.

  This article incorporates text from a publication now in the public domainSmith, William, ed. (1854–1857). "Bithynium". Dictionary of Greek and Roman Geography. London: John Murray.

Coordinates: 40°44′22″N 31°36′42″E / 40.739479°N 31.611561°E / 40.739479; 31.611561