During these years she also became deeply involved in spiritualism and Theosophy. These modes of spiritual engagement were widely popular across Europe and the United States—especially in literary and artistic circles—as people sought to reconcile long-held religious beliefs with scientific advances and a new awareness of the global plurality of religions.

Theosophy is an esoteric religious movement established in the United States during the late nineteenth century. It was founded largely by the Russian émigrée Helena Blavatsky and draws its beliefs predominantly from Blavatsky's writings. Categorised by scholars of religion as part of the occultist current of Western esotericism, it draws upon both older European philosophies like Neoplatonism and Asian religions like Hinduism and Buddhism.