Design of this stamp celebrated the 50th anniversary of the 19th Amendment, which gave women the right to vote. The Seneca Falls Convention in 1848 is considered the first serious demand for enfranchisement of American women. After the Civil War, agitation by women for the right to vote became increasingly strong. A schism among feminists over the proposed 15th Amendment, which gave black men the right to vote, came when some of the prominent female leaders refused to endorse the amendment. Two groups fighting for the same end developed, and they did not merge until 1890. In that year Wyoming entered the Union and became the first state with general women's suffrage.