​NICOMEDES I., son of Zipoetes, king of Bithynia (c. 278–248 B.C.). He made himself master of the whole country and put to death his brother, who had set himself up as an independent ruler. He enlarged and consolidated the kingdom, founded the great city of Nicomedia as the capital, and fought successfully for some time with Antiochus of Syria. His reign seems to have been prosperous and uneventful; the year of his death is uncertain.