The (Roman) theatre in the Asklepieion of Pergamon was built under Emperor Hadrian (Roman Emperor from 117 A.D. to 138 A.D.). Presumably, however, it is a superstructure of a previous Greek building. In the middle of the lower tier there was a box of honour, the recess of which is visible in the rows of seats. Only remains of the wall of the stage house remain.

The cult of the god of healing, Asklepios, was already established in Pergamon in the 4th century B.C. and was initially hereditary in the family of a certain Archias, the founder of the cult. Under Eumenes II it was elevated to the status of a state cult. The cult mainly consisted of natural healing practices (water and mud treatment, roundabouts, deep sleep, dream interpretation) combined with the religious activity of a large pilgrimage centre. The Asklepieion in its today known design can be traced back to an extension in the time of the Roman emperor Antoninus Pius. However, post-excavations have also uncovered remains of the Hellenistic and even older construction phases. In the 2nd century A.D. the sanctuary was the most important Asclepius in the ancient world.

Access to the Asklepieion was made possible by an 820-metre-long magnificent street, the first part of which, at least, had passed through an entrance gate when via tecta was vaulted. Columned halls accompanied the street, which was up to 18.50 metres wide, on both sides.

In the valley of the later Asklepieion some ceramic fragments of prearchaic and archaic times were discovered. The few remaining remains of the oldest buildings, however, date from the late 5th century BC and do not allow any judgement to be made about the appearance of the place of worship.
The source of the sanctuary, situated on a so-called rock bar, was probably already enclosed at this time and marked as a cult mark by a staircase running from west to east.

Around the middle of the 3rd century BC the appearance of the sanctuary changed decisively: for the first time the buildings were aligned according to a uniform concept in the four main directions, the buildings in the centre of the sanctuary became denser and the size of the individual buildings increased.
Behind this revaluation and monumentalization was possibly a stronger promotion of the Asclepius cult by the attalid royal house, which led to the more representative character.

The Roman sanctuary was a courtyard of 110 × 130 metres surrounded by buildings and halls, with a large forecourt and a propylon in front of it to the east, where the ceremonial street ended.

On the southeast corner of the area stood a two-storey rotunda, almost 60 metres in diameter on the outside, the upper floor of which was divided by inwardly directed semicircular niches.
The building, which had a normal roof, was used for the spa and was connected to the cult centre of the complex, the holy, radioactive spring, by an 80-metre-long underground corridor.

South of the propylon and thus at the edge of the court area was the Roman temple for Asklepios Soter or Zeus Soter Asklepios. The building is a smaller replica of the Pantheon in Rome and, with a dome diameter of 23.85 metres, had the largest brick dome of the Roman Empire at the time of its construction and probably of the entire world.