The Chorus speaks before Acts I, III, and IV and delivers the Epilogue at the end. The Prologue to Act I gives the exposition of the narrative material needed by the audience to understand the subsequent action. In the Prologue, the chorus narrates Faustus’s biography, compares him to Icarus, and foreshadows Faustus’s death. The Prologue, then, really gives the summary of the entire play, and as we watch the play we anxiously anticipate the fulfilment of what the Prologue has announced.
The Prologue to Act III narrates the fabulous journey of Faustus and gives us narrative material which Marlowe could not present dramatically. Here the Chorus is a conventional shorthand device which enables the dramatist to narrate rather than show by dramatic action. The Prologue to Act III tells us what Faustus has done before he came to Rome in Act III. The Prologue to Act IV does much the same thing because it introduces us to Faustus at the time of his return to Germany and the Court of the Emperor. As Epilogue the Chorus provides the conventional moral comment on the action of the play.