 Vince Gilligan wrote "Tithonus" in an attempt to create a story wherein immortality is portrayed as scary. The episode was based on three real aspects of history: Arthur Fellig, the Greek myth of Tithonus, and the yellow fever epidemic. In addition, several of the scenes were filmed on the sets from NYPD Blue, whose sets were located just across from The X-Files studios. The character of Alfred Fellig in "Tithonus" has thematically been compared to the Tithonus in Alfred, Lord Tennyson's dramatic monologue of the same name. In addition, themes of immortality and escaping death were revisited in the eighth season episode "The Gift".
