The earliest findings suggests that the Pergamon (or Pergamum, today's Bergama) was settled as early as the 8th century B.C. Considering its distant location from the sea, Pergamon was probably not a Greek settlement and yet little is known about the earlier centuries. The first record of history to the city is in 399 B.C. and it was under a Greek ruler.
Pergamon emerged as a power kingdom under the Attalids dynasty after territorial struggles between the generals of Alexander the Great, Seloucus I Nicator of Syria and Lysimachos, who was slain at the battle of Compedion in 281 BC by Seloucus I Nicator. Lysimachos had no heir to succeed him because earlier he had killed his own son Agathocles. After the death of Lysimachos, Pergamon was founded by Philetaerus who was the commander of Pergamon and was in charge of Lysimachos's treasure in the fortress of the acropolis or upper city. Philetaerus used this treasure to consolidate his position and his new kingdom.
The acropolis sits on an impressive steep ridge between the two tributaries of the Caicus river. The ridge is naturally fortified on all but the South side which slopes down to the Caicus valley base. The Caicus valley provides access from Pergamon to the Aegean coast and to the port town of Elaea in the West and the Persian Royal Road to the East.
During the Roman Imperial period the city continued to expand southward and spread over the plain and the area occuppied today by modern Bergama. The large Sanctuary of the Egyptian Gods (the "Kizil Avlu"), numerous bridges, and remains of the Roman stadium, theater, and amphitheater remain visible today.
During the reign Eumenes II (197-159 B.C.) Pergamon eached its peak. The kingdom had grown to include most of western Anatolia and was rich in agriculture and industry. Noted industrial exports included textiles, fine pottery, and "Pergamene paper" or parchment. The last industry developed when Ptolemy, reportedly jealous of the growing fame of the library in Pergamon, prohibited the export of papyrus from Egypt. The envied library possessed some 200,000 volumes. These later went to enrich Mark Antony's rival library in Alexandria. Pergamon rivalled Athens and Alexandria as centers of Hellenic culture. The city possessed one of the greatest libraries of antiquity, monumental gymnasia, and numerous religious sanctuaries, including the Asklepion outside the city walls. Pergamon was a haven for noted philosophers and artists and was the center of a major movement in Hellenistic sculpture. The Attalids supported the arts and learning in Pergamon and elsewhere and made major donations, such as the Stoa of Attalos II in Athens.
After a slight decline in the 1st century A.D. Pergamon went through a second period of greatness in the 2nd century A.D. New monumental structures were erected, including the large (ca. 300 x 100 m) sanctuary to the Egyptian gods in the center of the Roman city. The Sanctuary of Asklepios grew in fame and was considered one of the most famous therapeutic and healing center of the Roman world. Galen, after Hippocrates the most famous physician of antiquity, was born at Pergamon and received his early training at the Asklepion. By the end of the 2nd century A.D. Pergamon had become an important Christian center and the monumental Temple of Serapis in the sanctuary to the Egyptian gods was converted to a church. Weakening of the Pax Roma resulted in economical decline consequently Pergamon lost much of its importance. In Byzantine times A.D. 716 the city was sacked by the Arabs, another wall was built higher up the hill, enclosing a still smaller area, to provide protection against threatening Arab invasions followed by also the Seljuks. In the later centuries, Pergamon was occupied by the Ottomans, 14th century, and thereafter the city on the hill was abandoned and fell into decay, while the new town, Bergama grew up on the south side of the hill.