There are two theatre structures at Ephesus, the Great Theatre and the smaller Odeion. An inscription tells us that the theatre was commissioned around 150 AD by the wealthy benefactor Publius Vedius Antoninus and his wife Flavia Papiane. The building is located at the northern edge of the State Agora in close proximity to the Pryteneion, and has been interpreted both as a city council chamber and as a small concert hall. The structure, which resembles a small theatre, most likely served both functions.
The building features a relatively small cavea, a sunken semi-circular orchestra, and a shallow stage. The stage could be approached from either side using sloping parodos ramps and was backed by five doors leading to the Basilica Stoa. The building could be accessed through doors in the Basilica; through large arched doors at the end of the parodoi; and through an arched passageway leading to the top of the lower cavea seating area.
Greek and Roman theatres typically provided little protection from the weather other than retractable awnings. Smaller structures such as the Odeion and Bouleuterion however, were typically covered with a roof, comprised of wooden battens covered with clay tiles, supported by large triangular wooden trusses. As there are no water runoff channels in the orchestra, the Odeion was probably covered with such a roof. A narrow corridor with its deep drain separating the Odeion from the Basilica was a trough for rainwater shed by the roofs of both buildings.