Construction on the Theatre of Delos began shortly after 314 BC and was completed 70 years later.

The koilon (cavea), the audience area, was supported by a sturdy marble retaining wall. It is divided into two sections, upper and lower, of 26 and 17 tiers, respectively, with a seating capacity of approximately 6,500 spectators.

The seats in the first row (the proedria) have been best preserved and are the only seats with back support, as they were reserved for honoured persons.

The semicircular orchestra, which was the main part of the theatre, was closed on its straight side by the skene, the stage-building and dressing rooms, a rectangular structure with the external dimensions of 15.26 x 6.64 m. with three entrances on the east side and another on the west.

In front of the skene was the proskenion, a colonnade 2.67 m. high with Doric semi-columns between which were movable painted panels.

The metopes on the proskenion entablature were decorated with relief tripods and bulls’ heads.

Southwest of the theatre has preserved the remains of altars and sanctuaries dedicated to Artemis-Hecate, Apollo, Dionysus, Hermes and Pan.

An impressive structure is the great cistern of the Theatre, which collected rainwater from the cavea via a duct running around the orchestra. In its roof, which was supported on eight elegant granite arches, were well-mouths from which the water was drawn.