Vermont was admitted to the newly established United States as the fourteenth state in 1791. Vermont is one of the four U.S. states that were previously sovereign states (along with Texas, California, and Hawaii). During the mid-19th century, Vermont was a strong source of abolitionist sentiment, although it was also tied to King Cotton through the development of textile mills in the region, which relied on southern cotton. It sent a significant contingent of soldiers to participate in the American Civil War.