Pergamon had the second best library in the ancient world, after Alexandria. When the Ptolemies stopped exporting papyrus, partly because of competitors and partly because of shortages, they invented a new substance to use in codexes, called pergamum or parchment after the city. This was made of fine calf skin, a predecessor of vellum and paper.
Founded by a eunuch who left the land to his nephew, 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.
The Attalids were among the most loyal supporters of Rome among the Hellenistic successor states. For support against the Seleucids, the Attalids were rewarded with all the former Seleucid domains in Asia Minor. When Attalus III died without an heir in 133 BC he bequethed Pergamum to Rome, in order to prevent a civil war.
The present-day, Turkish, name of the city is Bergama.