Helen Mathers #1 - pseudonym of Ellen Buckingham Mathews Reeves (1853-1920) Due to a confusion of titles, some sources (not excluding WorldCat) attribute a number of books by Scottish novelist Anne S. Swan to Mathers. Mathers published a short novel entitled "The Land o' the Leal, by the Author of Comin' Thro' the Rye" in 1878. Swan published "The Land o' the Leal" (same title, completely different book) using her male pseudonym David Lyall, in 1896. Conflating the two different novels with the same title has led some people to assume (erroneously) that David Lyall is Mathers's pseudonym. It is not.
Helen Mathers #2 - academic, fl. 1990s, specializing in Victorian and women's history.