Pergamon or Pergamum ,also referred to by its modern Greek form Pergamos was a rich and powerful ancient Greek city in Mysia. It is located 26 kilometres (16 mi) from the modern coastline of the Aegean Sea on a promontory on the north side of the river Caicus (modern-day Bakırçay) and northwest of the modern city of Bergama, Turkey.
During the Hellenistic period, it became the capital of the Kingdom of Pergamon under the Attalid dynasty in 281–133 BC, who transformed it into one of the major cultural centres of the Greek world. Many remains of its impressive monuments can still be seen and especially the outstanding masterpiece of the Pergamon Altar. Pergamon was the northernmost of the seven churches of Asia cited in the New Testament Book of Revelation.
The city is centered around a 335-metre-high (1,099 ft) mesa of andesite which formed its acropolis.
This mesa falls away sharply on the north, west, and east sides, but
three natural terraces on the south side provide a route up to the top.
To the west of the acropolis, the Selinus River (modern Bergamaçay) flows through the city, while the Ketios river (modern Kestelçay) passes by to the east.
Pergamon lies on the north edge of the Caicus plain in the historic region of Mysia in the northwest of Turkey. The Caicus river breaks through the surrounding mountains and hills at this point and flows in a wide arc to the southwest. At the foot of the mountain range to the north, between the rivers Selinus and Cetius, there is the massif of Pergamon which rises 335 metres above sea level. The site is only 26 km from the sea, but the Caicus plain is not open to the sea, since the way is blocked by the Karadağ massif. As a result, the area has a strongly inland character. In Hellenistic times, the town of Elaia at the mouth of the Caicus served as the port of Pergamon. The climate is Mediterranean with a dry period from May to August, as is common along the west coast of Asia Minor.
The Caicus valley is mostly composed of volcanic rock, particularly andesite and the Pergamon massif is also an intrusive stock of andesite. The massif is about one kilometre wide and around 5.5 km long from north to south. It consists of a broad, elongated base and a relatively small peak - the upper city. The side facing the Cetius river is a sharp cliff, while the side facing the Selinus is a little rough. On the north side, the rock forms a 70 m wide spur of rock. To the southeast of this spur, which is known as the 'Garden of the Queen', the massif reaches its greatest height and breaks off suddenly immediately to the east. The upper city extends for another 250 m to the south, but it remains very narrow, with a width of only 150 m. At its south end the massif falls gradually to the east and south, widening to around 350 m and then descends to the plain towards the southwest.
Settlement of Pergamon can be detected as far back as the Archaic period, thanks to modest archaeological finds, especially fragments of pottery imported from the west, particularly eastern Greece and Corinth, which date to the late 8th century BC. Earlier habitation in the Bronze Age cannot be demonstrated, although Bronze Age stone tools are found in the surrounding area.
The earliest mention of Pergamon in literary sources comes from Xenophon's Anabasis, since the march of the Ten Thousand under Xenophon's command ended at Pergamon in 400/399 BC.Xenophon, who calls the city Pergamos, handed over the rest of his Greek troops (some 5,000 men according to Diodorus) to Thibron, who was planning an expedition against the Persian satraps Tissaphernes and Pharnabazus, at this location in March 399 BC. At this time Pergamon was in the possession of the family of Gongylos from Eretria, a Greek favourable to the Achaemenid Empire who had taken refuge in Asia Minor and obtained the territory of Pergamon from Xerxes I, and Xenophon was hosted by his widow Hellas.
In 362 BC, Orontes, satrap of Mysia, based his revolt against the Persian empire at Pergamon, but was crushed. Only with Alexander the Great was Pergamon and the surrounding area removed from Persian control. There are few traces of the pre-Hellenistic city, since in the following period the terrain was profoundly changed and the construction of broad terraces involved the removal of almost all earlier structures. Parts of the temple of Athena, as well as the walls and foundations of the altar in the sanctuary of Demeter go back to the fourth century.