Bithynia was an old kingdom of a Roman province in the northwest of Asia Minor. It was at the coast of the Black Sea. It was named after the Bithyni, a tribe that moved there from Thrace. It was an important territory for the Roman empire. Bithynia was also the site of early Christian activities in the first and second centuries AD.
- Matthew Bunson, Encyclopedia of the Roman Empire (New York: Facts On File, 2002), p. 76
- "Ancient Districts". Thracian Ltd. 2011. Archived from the original on 14 January 2015. Retrieved 2 April 2015.
- Graham Stanton, Studies in Matthew and Early Christianity (Tübingen, Germany: Mohr Siebeck, 2013), p. 406
- Stanley Jonathon Storey, Bithynia: history and administration to the time of Pliny the Younger (Ottawa, National Library of Canada, 1998) ISBN 0-612-34324-3