an ancient kingdom of Asia, formerly known by the names of Mygia, Mygdonia, Babrycia, Mariandynia. Mariandyria, and Bitiynia. It was bounded on the west by the Bosporus Thracus and part of the Pontus, on the south by the river Rhodacus and mount Olympus, on the north by the Euxine sea, and on the east by the river Parthenius. The chief cities were Myrlea, Nicomedia, Chalcedon, Heraclea, and Prusa.

As to its history, we find nothing of moment recorded; except the famous conduct of Prussias, one of its kings, in delivering up to the Romans Hannibal, the great Carthaginian general, who fled to him for protection. His great grandson Nicomedes IV. bequeathed the kingdom to the Romans. From them it was taken by the Turks, to whom it still remains subject, but has no modern name.