Elizabeth Whittingham cited correspondence from readers, particularly Catholics like Father Murray and Peter Hastings, which raised questions that ultimately prompted changes to the mythology of Middle-earth as acknowledged by Tolkien and his son Christopher. She noted that Tolkien sought to make his "secondary world" compatible with his "primary world", and so he reconsidered his focus on metaphysical and philosophical explorations from the 1950s and his revisions gradually moved the texts of his legendarium closer in alignment with biblical accounts and Christian ideals. Whittingham observed that Glorfindel is a notable exception to Tolkien's later stance on abandoning one of his oldest concepts, reincarnation through rebirth, and that he is Tolkien's first attempt of contemplating the portrayal of a reincarnated elf.