Bithynia

Bithynia (; Koine Greek: Βιθυνία, romanized: Bithynía) is a geographical region of northwestern Asia Minor (in present-day Turkey), adjoining the Sea of Marmara, the Bosporus, and the Black Sea. It borders Mysia to the southwest, Paphlagonia to the northeast along the Black Sea coast, and Phrygia to the southeast towards the interior of Asia Minor.

HellenisticBithynia was an independent kingdom from the 3rd century BC. Its capital Nicomedia was rebuilt on the site of ancient Astacus in 264 BC by Nicomedes I. Bithynia was bequeathed to the Roman Republic in 74 BC, and became united with the Pontus region as the province of Bithynia and Pontus.

In the 7th century it was incorporated into the Byzantine Opsikiontheme. It became a border region to the Seljuk Empire in the 13th century, and was eventually conquered by the Ottoman Turksbetween 1325 and 1333.