The historical figure remembered for her advocacy of women's rights in the 19th century is Elizabeth Cady Stanton. Stanton was a key leader in the early women's rights movement in the United States and co-organized the Seneca Falls Convention in 1848, which was the first women's rights convention. She was primarily known for her declaration, the "Declaration of Sentiments," which outlined the demands for gender equality and suffrage. Stanton's efforts paved the way for future advocacy on women's issues, and her work contributed significantly to the eventual passage of women's suffrage in the early 20th century.