The first function of a tragic chorus was to chant an entrance song called a parodos as they marched into the orchestra. Once the chorus had taken its position in the orchestra, its duties were twofold. It engaged in dialogue with characters through its leader, the Coryphaeus, who alone spoke the lines of dialogue assigned to the chorus. The modern reader of Greek Tragedy, whether in English or even in the original Greek, finds it very difficult to appreciate the effect of these choral songs which are devoid of their music and dance. Structure Tragedy has a characteristic structure in which scenes of dialogue alternate with choral songs.
Most tragedies begin with an opening scene of expository dialogue or monologue called a prologue.
After the prologue the chorus marches into the orchestra chanting the parodos . Then follows a scene of dialogue called an episode, which in turn is followed by the first stasimon. The exodos is in general a scene of dialogue, but, as in the case of episodes, sometimes songs are included, especially in the form of a kommos . Some tragedies have one more or less episode and stasimon.