Annie Wood Besant was born on 1 October 1847 in London. Her early adult life was spent as one of Victorian England's most visible radical reformers: a freethinker who left the Church of England, a birth control advocate whose 1877 prosecution alongside Charles Bradlaugh for publishing contraceptive information became a national scandal, and a labor organizer who helped lead the 1888 London matchgirls' strike. Her public reputation before 1889 rested entirely on this activist and secularist record, made her later turn toward Theosophy all the more striking to contemporaries who had known her as a leading skeptic.
In 1889 Besant read Helena Blavatsky's The Secret Doctrine, met Blavatsky shortly afterward, and underwent what she described as a complete conversion to Theosophical belief. She became one of Blavatsky's closest associates in the Society's final years and, after Blavatsky's death in 1891, rose to become the Theosophical Society's second president in 1907, a position she held until her own death. She died in Adyar, India, the Society's international headquarters, on 20 September 1933.
Her earlier activist career had already made her a genuinely national figure well before Theosophy: she edited freethought publications, campaigned publicly for secularism and workers' rights, and was among the most recognized women in English public life of the 1880s. That she redirected the full force of that public standing and organizing skill toward Theosophy after 1889 is a large part of why the Society grew so rapidly in scale and public visibility under her subsequent leadership, compared with its smaller and more insular character under Blavatsky.