What Dreams May Come in the book are derived from my wide range of reading." One of Matheson's influences was Harold W. Percival, an adherent of Theosophy, a belief system with a strong Eastern and Hindu influence. The story also shares the same theme of the ancient Greek myth Orpheus and Eurydice, in which the gifted musician makes a challenging journey to Hell to retrieve his wife. One character quotes from the writings of 18th century Christian mystic Emanuel Swedenborg. Matheson bases his descriptions of the death experience itself on studies by Elisabeth Kübler-Ross and Raymond Moody. When reading these accounts, Matheson found that
Orpheus whom he called Apollo. One early morning he went to the oracle of Dionysus at Mount Pangaion to salute his god at dawn, but was ripped to shreds by Thracian Maenads for not honoring his previous patron (Dionysus) and buried in Pieria. Here his death is analogous with that of Pentheus, who was also torn to pieces by Maenads; and it has been speculated that the Orphic mystery cult regarded Orpheus as a parallel figure to or even an incarnation of Dionysus. Both made similar journeys into Hades, and Dionysus Zagreus suffered an identical death. Pausanias writes that Orpheus was