In 1875, Blavatsky and Henry Steel Olcott established a research and publishing institute called the Theosophical Society. Blavatsky defined Theosophy as "the archaic Wisdom-Religion, the esoteric doctrine once known in every ancient country having claims to civilization". One of the main purposes of the Theosophical Society was "to form a nucleus of the Universal Brotherhood of Humanity, without distinction of race, creed, sex, caste or color". Madame Blavatsky saw herself as a missionary of this ancient knowledge. She travelled the world and wrote books about the occult including "Isis Unveiled" and "The Secret Doctrine".