Maxentius vs Prusias I

Maxentius was proclaimed emperor in Rome by the Praetorian Guard and the Roman populace, who resented the tax policies of Galerius. He initially ruled as a usurper but later claimed the title Augustus. His reign was centered in Italy and Africa, challenging the Tetrarchic system.

Maxentius allied with his father Maximian, who had come out of retirement to support him. Maximian married his daughter Fausta to Constantine to secure an alliance, but the alliance was short-lived. Maximian later betrayed Maxentius by attempting to usurp his throne.

Maxentius began construction of the Basilica Nova in the Roman Forum, a massive civic building with a vaulted ceiling. The basilica was completed by Constantine after Maxentius's death. It remains one of the largest ancient Roman structures and a symbol of Maxentius's building program.

Maxentius led his forces against Constantine at the Milvian Bridge near Rome. His army was defeated, and Maxentius drowned in the Tiber while attempting to retreat. The battle marked Constantine's rise as sole ruler of the West and was later associated with Constantine's conversion to Christianity.

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.