Short answers, pulled from the story.
The adjective esoteric first appeared in the second century CE within a satire authored by Lucian after 180. This ancient Greek term denoted belonging to an inner circle of thinkers rather than public discourse.
Antoine Faivre published criteria defining Western esotericism in 1992, listing six fundamental characteristics. Four traits were intrinsic including correspondences between macrocosm and microcosm and living nature imbued with life force while two secondary traits involved transmission from master to disciple and practice of concordance among world religions.
Hermeticism emerged in the Hellenistic Eastern Mediterranean during Late Antiquity as Egyptian school of thought named after Hermes Trismegistus. Texts attributed to him appeared in second and third centuries including Corpus Hermeticum and Asclepius.
Rosicrucian Manifestos published Germany between 1614 and 1616 purported secret brotherhood founded centuries before by Christian Rosenkreutz likely literary creation Johann Valentin Andreae.
Spiritualism emerged United States 1840s spreading North America Europe allowing communication spirits deceased during séances. Andrew Jackson Davis Allan Kardec articulated full theological worldviews movement.
Henry Corbin instigated École pratique des hautes études Sorbonne establish world first academic post study esotericism 1965 chair History Christian Esotericism. François Secret specialist Christian Kabbalah held position little interest developing wider field research.