  Not long after her conversion, Fell began to express her Quaker beliefs in print, starting with False Prophets, Antichrists, Deceivers in 1655. She was the author (or co-author) of at least 23 works in total, mostly in the form of short pamphlets. Some of her more substantial works—including A Call to the Universall Seed of God (1665), Womens Speaking Justified (1666; second edition, 1667), and A Touch-Stone: or, A Perfect Tryal by the Scriptures (1667)—were written during the period of her imprisonment in Lancaster Castle (1664–68). Following her death, several of her works were collected together and published as A Brief Collection of Remarkable Passages and Occurrences (1710). Despite its 535 pages, this collection is nevertheless incomplete and includes only a small sample of letters. Her works are now available in their original form in online databases such as Early English Books Online, or in selective modern anthologies such as Wallace (1992), Booy (2004), and Garman et al. (1996). Elsa F. Glines has published 164 of Fell’s surviving letters in her collection The Letters of Margaret Fell (2003).