Pergamon, or Pergamum, is an ancient Greek city in modern-day Turkey, in Mysia, today located 16 miles (26 km) from the Aegean Sea on a promontory on the north side of the river Caicus (modern day Bakırçay), that becomes the capital of the Kingdom of Pergamon during the Hellenistic period, under the Attalid dynasty, 281–133 BCE.

Pergamon is cited in the book of Revelation as one of the seven churches of Asia.

Today, the main sites of ancient Pergamon are to the north and west of the modern city of Bergama.The Attalid dynasty is a Hellenistic dynasty that rules the city of Pergamon after the death of Lysimachus, a general of Alexander the Great.

The Attalid kingdom is the rump state left after the collapse of the Lysimachian Empire.

One of Lysimachus' officers, Philetaerus, takes control of the city in 282 BCE.

The later Attalids are descended from his father, and they expand the city into a kingdom.

Attalus I proclaims himself King in the 230s BC, following his victories over the Galatians.

The Attalids rule Pergamon until Attalus III bequeaths the kingdom to the Roman Republic in 133 BCE to avoid a likely succession crisis.