There are several differences between "Hippolyte et Aricie" and "Phèdre". Some of these are due to differences in genre between French Classical drama and "tragédie en musique". Racine observes the Aristotelian unities of time and space: the action of his play is confined to a single location and takes place within 24 hours. On the other hand, each act in Pellegrin's libretto has a different setting. Pellegrin also provides a happy ending, at least for the lovers Hippolyte and Aricie, whereas Racine is wholly tragic; Hippolyte does not rise from the dead. Pellegrin's drama has a major change in focus: Racine's play centres on Phèdre; she is still important in Pellegrin's version, but he pays much more attention to Thésée. For instance, the entirety of the second act is devoted to Thésée's visit to the Underworld. Graham Sadler writes: