In the middle of the 2nd century A.D., the (Roman) theatre of Side was restored to its present condition. About a century later the orchestra was rebuilt for arena fights.
The theatre was built on the transition to the headland. In the absence of a hill, a double arched gallery with a corridor was built. 23 vaulted passages lead to the Diazoma between the first and second levels. It is presumed that above the uppermost rows of seats - as for example in the Perge Theatre - a circumferential arched gallery was erected to support the acoustics. Unfortunately, the remains of this gallery have not been preserved. It was probably destroyed in the course of time by earthquakes, the stones fell and were used to build the Byzantine defences. The two-storey stage house was 65 m long and 10 m wide. The height of the two floors was 20 metres. Five doors lead to the neighbouring trading agora. Some sources report the temporary use of the theatre as a slave market.

The ancient Side is situated on a flat peninsula with harbour facilities at the tip. According to ancient tradition, Side was founded around the 7th century BC. The most important ruins date from the Roman epoch, the 2nd and 3rd centuries AD. Other important buildings were built when Side became a bishop's seat in the 5th or 6th century. The town was probably abandoned in the 10th century. An earthquake destroyed many buildings.

Side is one of the oldest cities on the Turkish south coast. It is assumed that the first settlement of the peninsula already took place in the 2nd millennium BC. The name of the city comes from an ancient Anatolian language and means "pomegranate" (Turkish: Nar) The pomegranate also adorns coins minted from the 5th century BC onwards.

By the expansion of the port Side rose in Hellenistic time to a prosperous and important commercial metropolis with about 40,000 inhabitants. At the beginning of the 1st century the city fathers arranged themselves with the Cilician pirates and Side became an important slave market. The income from the slave market was finally lost after Pompeius put an end to piracy in 67 BC.

In the course of history, the city flourished as part of the Roman province of Pamphili and experienced a period of prosperity until the middle of the 3rd century AD. The wealth of this time is documented by generous buildings, temples and boulevards. These buildings still shape the image of the ancient city today. However, the inner city wall, for example, testifies to the fact that the period of peace was only of relatively short duration.

With the collapse of the Roman Empire, Side also experienced its decline. In particular, the siltation of the port contributed to this. One gave up a large part of the city and withdrew into the city area within the walls. It was not until the 5th and 6th centuries that people settled again outside the city walls. Especially the up-and-coming Antalya attracted people.

Already in the 3rd century A.D. an active Christian community in Side was reported. Files of the Christian trials from the times of the emperor Diocletian prove this. In Byzantine times, Side was elevated to the status of a bishop's seat, but the city never regained its former importance.
At the time of the Arab raids in the 7th century A.D. many inhabitants migrated to Antalya. From then on it became quiet around the once so splendid city. In the 11th century the city once again made a name for itself as a pirate's nest, but soon sand dunes lay over the ruins.