H.S. Olcott is a

Helena Petrovna Blavatsky (née Hahn von Rottenstern; 12 August [O.S. 31 July] 1831 – 8 May 1891), often known as Madame Blavatsky, was a Russian and American mystic and writer who co-founded the Theosophical Society in 1875. She gained an international following as the primary founder of Theosophy as a belief system. Born into an aristocratic family in Yekaterinoslav, Blavatsky traveled widely around the empire as a child. Largely self-educated, she developed an interest in Western esotericism d…