According to legend, Archias, an esteemed person and the first Prytan of Pergamon, gets his leg injured while hunting in Greece. He receives treatment in the famous Epidaurus Asclepion in Greece. After the success of the treatment, in order to express his gratitude to the god of healing, he brings the cult of Asclepius to Pergamon.
Prehistoric remains unearthed during excavations at the site of the Asclepion indicate that this area had been used before 4th century BC. However, it gained importance after the 4th century BC. Treatment methods implemented in this sacred area, of which plan took its final shape during the reign of Emperor Hadrian (117-138 AD), and physicians such as Galen became very famous especially in the Roman Period.
In the Roman Period, the sacred area was connected to the city of Pergamon via a vaulted way called Via Tecta. This way was entered through a large arched gate, called "Ruined Gate" (Viran Kapı), south of the Roman theatre in the lower city. The patients were inspected here by priest-physicians (Asclepiades), terminally ill people and pregnant women were not accepted. It is said that an inscription on the gate of entry read, "For the Sacredness of all Gods, Death is Forbidden to Enter Asclepion". The sacred way (Via Tecta) was leading to the entrance (propylon) of Asclepieion and protecting patients from bad weather conditions. The last section of the way was decorated with columns during the reign of Emperor Hadrian. In both sides of the colonnaded way, all kinds of offerings and items for healing were sold. In the southern part of the colonnaded way, there is a mausoleum of probably a notable person or a hero, dated to the era of Emperor Augustus (27 BC-14 AD).
The quadratic structure east of the northern gallery was the emperor's hall and at the same time, it was used as a library. In the niches seen on the north, east and south walls of the hall, there were wooden shelves in which inscriptions were stored. The middle niche of the east hall was housing a statue of Emperor Hadrian, which is displayed today in the Bergama Museum. Due to the slope of the ground downward to the south, the southern gallery is a two-story structure with its vaulted ground floor with two naves and the colonnaded gallery.
The western gallery is, like the northern gallery, in the Ionic style. The door in the inner middle part of the gallery leads to another gallery extending in the east-west direction. In the south part of the Doric gallery is a rectangular exedra, of which walls are decorated with paintings. The gallery was built during the reign of Eumenes (2nd century BC), when the sacred area of Asclepion was expanded towards west. Although excavation works have not been finished yet, this gallery is presumed to belong to a gymnasium or to a dormitory for visitors of patients. In the south end of the western gallery (in the area where the toilets built in the Roman Period are located), there is a big hall. This hall, of which floor and walls are covered with marble, was probably a "Banquet Hall".
In the earliest phases of the sacred area, there were basins and fountains around three springs. Later, temples dedicated to Hygieia, daughter of Asclepius Soter (Asclepius the Saviour), and to Apollo, father of Asclepius, were built, which did not reach the present-day. The sleeping rooms, of which foundations can only be seen today, are dated to the Hellenistic Period. The Asclepion took its final shape with the structures built in the Roman Period.
During the renovations in the Roman Period, the three temples, sleeping rooms, the sacred spring and basins originating from the Hellenistic Period were left in their places.