Based on the theories of Aristotle and Horace, the neoclassic rules of decorum required a play only to show what was suitable on stage and to leave scenes that were especially gruesome or violent offstage, to be related later through narration. For example, Horace wrote that:
you will not bring...
on to the stage anything that ought properly to be taking place behinds the scenes, and you will keep out of sight many episodes that are to be described later by the eloquent tongue of a narrator.
As an example, Horace advised strongly that Medea's murder of her children take place off stage.
Neoclassical playwrights were also concerned to follow Aristotle's three unities of time, place, and action. These dictated that the timespan of a drama be no more that 24 hours, that it take place in one location, and that the plot should focus on one principle story line.
it is easy to see that Racine adhered to these neoclassic ideals in Phaedra. For example, the entire action of the play takes place with a single day. It also occurs in a single location, the royal court in Troezen in Greece. Finally, it focuses tightly on one story line, which is Phaedrus's love for Hippolytus, her stepson, a forbidden, incestuous passion.
Decorum is also adhered to in having the dramatic and violent demise of Hippolytus happen off stage. He is killed in his chariot by the death thrashings of the horned sea monster summoned by Neptune at the request of Theseus. The information is reported, following Horace's rules, through narration, in this case by Theramenes, Hippolytus's tutor.