Claudiopolis, a titular see of Bithynia, in Asia Minor. Strabo (XII, 4, 7) mentions a town, Bithynium (Claudiopolis), celebrated for its pastures and cheese. According to Pausanias (VIII, 9) it was founded by Arcadians from Mantinea. As is shown by its coins, it was commonly called Claudiopolis after Claudius. It was the birthplace of Antinous, the favorite of Hadrian, who was very generous to the city; afterwards his name was added to that of Claudius on the coins of the city. Theodosius II (408-50) made it the capital of a new province, formed at the expense of Bithynia and Paphlagonia, and called by him Honorias in honor of the Emperor Honorius. Claudiopolis was the religious metropolis of the province (so in all “Notitime episcopatuum”). Lequien (I, 567) mentions twenty titulars of the see to the thirteenth century; the first is St. Autonomus, said to have suffered martyrdom under Diocletian; we may add Ignatius, a friend and correspondent of Photius.
The Turkish name for Claudiopolis is Bolou or Boli. It is now the chief town of a sanjak in the vilayet of Castamouni, with 10,000 inhabitants (700 Greeks, 400 Armenians, and few Catholics). The town is on the Filias Sou (River Billus). There are no important ruins, but many ancient fragments of friezes, cornices, funeral cippi, and stelae.