Prusias I

Prusias I besieged the Greek city of Byzantium, forcing it to pay tribute and acknowledge Bithynian supremacy. This campaign expanded Bithynian influence along the Bosporus and the Black Sea coast.

Prusias I waged war against Eumenes II of Pergamon, allying with the Galatians. The war ended with a Roman-brokered peace that forced Prusias to cede territory and pay indemnities, weakening Bithynia's position.

Prusias I granted asylum to the Carthaginian general Hannibal, who had fled from the Seleucid court after the defeat at Magnesia. Hannibal served as a military advisor to Prusias, helping him in conflicts against Pergamon.