The Roman theatre of Philippopolis (Latin: Theatrum Trimontense; Bulgarian: Пловдивски античен театър, Plovdivski antichen teatar) is one of the world’s best-preserved ancient Roman theatres, located in the city center of modern Plovdiv, Bulgaria, once the ancient city of Philippopolis. It was constructed in the 1st century AD, probably during the reign of Domitian. The theatre can host between 5,000 and 7,000 spectators and it is currently in use.
The spectator seats are orientated to the south, towards the ancient city in the lowland and the Rhodope Mountains. In outline, the theatre is a semi-circle with an outer diameter of 82 meters. The theatre itself is divided into the seating section (cavea) and the stage (orchestra). The cavea, the area in which people gathered, is hollowed out of a hill or slope, while the outer radian seats required structural support and solid retaining walls. The cavea was not roofed. The spectator seats surround the stage (orchestra), which has the shape of a horseshoe, 26.64 meters long, includes 28 concentric rows of marble seats, divided into two tiers by an aisle (diazoma). The upper part of the tiers is interrupted by narrow radial stairways, which divide the cavea into wedge-shaped sectors (kerkides). The theatre also has a podium, which supports the columns of the scaenae frons.
The stage building – the scaenae frons – is south of the orchestra. It has three floors and is a high wall of the stage floor, supported by columns. The proscenium is a wall that supports the front edge of the stage with ornately decorated niches off to the sides. The proscaenium, which is 3.16 meters high, and its facade is decorated with an Ionic marble colonnade with triangular pediments. The facade of the scenae, which overlooks the spectators’ area, consists of two two-storey porticos, the first in the Roman Ionic order and the second in the Roman-Corinthian order. The facade is cut through by three symmetrically located gates. The entrances to the orchestra, which are uncovered and vaulted, connect the cavea with the stage building. An underground vaulted passage begins from the centre of the orchestra, goes under the stage building and leads out of the theatre. Another vaulted passage, passing under the central bank of seats of the top tier, connects the cavea with the Three Hills area.
Similar to all the theatres on the territory of the Roman Empire, in the theatre of Trimontium the honorary spectator seats were inscribed. There were inscriptions not only for the representatives of the city council but also for magistrates, friends of the Emperor, etc. Some honorary inscriptions show that the building was used as the seat of the Thracian provincial assembly. Built with around 7,000 seats, each section of seating had the names of the city quarters engraved on the benches so the citizens knew where they were to sit.