Helena Blavatsky

Russian occultist who co-founded the Theosophical Society (1875) and wrote The Secret Doctrine — the foundational text of modern Theosophy, synthesizing Eastern religion, Western occultism, and evolutionary theory.

Theosophy as syncretic religion: Blavatsky's contribution was creating a synthetic spiritual framework that drew on Hindu, Buddhist, Kabbalistic, and Hermetic traditions, integrated with scientific evolutionary theory, to produce a unified cosmology accessible to late-Victorian seekers. Her claims (communication with Tibetan Mahatmas, esoteric knowledge of cosmic evolution) were widely debunked but the framework she created became the intellectual predecessor of virtually every significant 20th-century esoteric movement — Rudolf Steiner's Anthroposophy, Alice Bailey's work, much of the New Age movement.