Helena Petrovna Blavatsky (Russian: Елена Петровна Блаватская, Yelena Petrovna Blavatskaya, often known as Madame Blavatsky; née von Hahn; Ukrainian: Олена Петрівна Блаватська, Olena Petrivna Blavatska; 12 August [O.S. 31 July] 1831 – 8 May 1891) was a Russian author who co-founded the Theosophical Society in 1875. She gained an international following as the leading theoretician of Theosophy.
