The ancient greek theater was composed by three major parts: the Orchestra, the Scene and the main theater, called Koilon.
The Orchestra was the almost circular place, situated in front of the scene (stage) facing the audience. At the center of the orchestra was situated the Thymeli, which at the early years was meant to be an altar and later on, a place, where the leader of the chorus (koryphaios) was standing. Some archaeological research in the Athens aerea gave some clues for the existance of rectangular orchestras in some ancient greek theaters, but the circular shape was the dominant one and also the closest to the dionyssiac cult (the circle was supposed to have supernatural power). …