Bithynia was anciently inhabited by various nations, differing in their manners, customs, and language, namely the Bebryces, the Caucones, the Dolliones, the Cimmerii, and the Mariandyni occupied the northeast part.
Bithynia was named after the Bithynia one of the warlike Indo-European tribes that had emigrated from Thrace during the first quarter of the first millennium.
Bithynia came under Lydian rule in the seventh century. The province was conquered by the Persians in 546 BC and was included in the satrapy of Phrygia. Bithynia was conquered by the Greeks and the Romans and appeared to have attracted so much attention of its roads and strategic position between the frontiers of the Danube in the north and the Euphrates in the southeast.
The land was occupied by Alexander the Great in 334 BC. In 297 BC Zipoetes, a local Thracian chieftain, freed his country fro Lysimachus and assumed the royal title.
Nicomedes I (son of Zipoetes) established the first Dynasty of Bithynian kings and rules from 278 to 250 BC. In 264 BC he founded Nicomedia and made it capital.
Bithynia became a separate province in the 4th century AD, and continued to exist into the 8th century when Slav captives were settled there.
The origin of Bithynia Kingdom