When Pausanias visited the city in the 2nd century A.D., the city consisted of beautiful buildings, and following his steps, it is believed that the theater was at the foot of the Acropolis. The theater of Ancient Sikyon, was one of the most remarkable buildings and it is considered to be one of the most impressive theaters of this size. Typical architectural features of the theater are its two vaulted passages at the upper aisle, original Greek domes, and also the special drainage system, which runs through the orchestra branches through to the back of the stage building. Moreover, another architectural characteristic is the stairwell, a few steps of which are still preserved.
The architect that designed the theater selected the best location for its construction. He adjusted the natural landscape by dug a wide hollow. Most interesting, is that the front of the building has a view of the northeast, offering visitors the beauty of the Corinthian Gulf but also the summits of the mountains of Roumeli.
The total width of the theater is more than 122m, the seats are mostly carved into the rock and only a few of them, at the lowest western half, are revealed. The stone seats of the front row are made of limestone, with backs and arms, some of which are decorated with threads on their outer side. Their superiority and decorative construction indicate that there were intended to host VIPs, like the seats in Epidaurus. There were 60 rows of seat, separated by 16 vertical aisles.
Horizontally the auditorium was divided into three parts by two tiers. The visitor could enter the lowest tier through two vaulted corridors that crossed the parts of the auditorium, while the highest tier was accessible at the two ends. The eastern corridor was initially 5m long and 2,55m wide. These domes were built with squared boulders without mortar and constitute remarkable specimens of Greek domes. The orchestra occupies an area that was slightly bigger than half of the circumference of an almost perfect circle, with a diameter of 20, 04 m and dirt surface.
At the ancient theater of Sikyon possesses a noteworthy drainage system. There is a drainage ditch that crosses the orchestra in front of the benches of honor and is almost 1,25m wide and 1m deep, bridged by a stone slab, like in the Theater of Dionysius in Athens. At the end of the ditch there seems to have been an altar or fountain, which also crossed the orchestra, parallel to the wall of the proscenium and it was used to remove the dirty waters. This ditch ended in a third one, which crossed the center of the orchestra, vertically to the buildings of the stage and ended at some point at the right side. From the square bowl in the center of the orchestra, where the drainage ditches meet, starts an underground corridor, which passes under the buildings of the stage and ends behind them at a stairwell. This corridor was used by the actors and dramatists in order to pass unnoticed from the stage to the center of the orchestra, according to the “Charon staircase”.
The excavation of the lowest parts of the stage building, as well as the adjoining foundations on the eastern and western side, revealed something really important; remains of two backstage areas, the double entrance of the western sloping anodos (the way up). And parodos (the side way) that helped to establish the dates of the oldest building. Stone sloping ramps, carved onto the rock (3,25m high) led to the conclusion that the stage was 11 roman feet high, following the style of the Vitruvian rule. Behind them, two more sloping anodoi, ramps lead to the second floor of the stage building. The finding of the stone supports of the older stage that abolishes the theory related to the existence of a wooden stage, was very important. Simultaneously, the remains of columns, proving that the first stage was preserved until the roman times, when it was reconstructed were found.
The date of the theater can be only be estimated. Some relate it to the facts that took place in 251 B.C. and 168 B.C. while Pausanias refers to the middle of the 2nd century B.C. Excavations brought to light evidence that the theater dates back to the years before the 303 B.C., when Sykion was transferred to the plateau and was rebuilt. This date is also verified based on the architectural comparison to the theater of Epidaurus. According to the similarities, the architect of the one must have known about the existence of the other, but the antiquated style of the drainage ditch of the theater of Sykion demonstrates that this one is oldest than the other. So, its construction is correctly placed chronologically to the 4th century B.C. Its roman reconstruction possibly dates to after the destruction of Corinth, when a part of it was assigned to Sykion and the city got a significant political entity.