Pergamum was an ancient Greek city in modern-day Turkey, in Mysia, north-western Anatolia, 16 miles from the Aegean Sea, located on a promontory on the north side of the river Caicus (modern day Bakircay), that became the capital of the Kingdom of Pergamon during the Hellenistic period, under the Attalid dynasty, 281–133 BC. Today, the modern city of Bergama is located nearby.
The Attalid kingdom was the rump state left after the collapse of the Kingdom of Thrace.
The Attalids, the descendants of Attalus, father of Philetaerus who came to power in 281 BC following the collapse of the Kingdom of Thrace, were among the most loyal supporters of Rome in the Hellenistic world. Under Attalus I (241-197 BC), they allied with Rome against Philip V of Macedon, during the first and second Macedonian Wars, and again under Eumenes II (197-158 BC), against Perseus of Macedon, during the Third Macedonian War. For support against the Seleucids, the Attalids were rewarded with all the former Seleucid domains in Asia Minor.
The Attalids ruled with intelligence and generosity. Many documents survive showing how the Attalids would support the growth of towns through sending in skilled artisans and by remitting taxes. They allowed the Greek cities in their domains to maintain nominal independence. They sent gifts to Greek cultural sites like Delphi, Delos, and Athens. They defeated the invading Celts. They remodeled the Acropolis of Pergamum after the Acropolis in Athens. When Attalus III (138-133 BC) died without an heir in 133 BC he bequeathed the whole of Pergamon to Rome, in order to prevent a civil war.
The first Christian bishop of Pergamon, Antipas, was believed to have been martyred here in 92 AD.