the Alamo. The state's nickname was solidified during the Mexican–American War when President James K. Polk of Tennessee issued a call for 2,800 soldiers from the state, and more than 30,000 volunteered. Between the 1790s and 1820s, additional land cessions were negotiated with the Cherokee, who had established a national government modeled on the U.S. Constitution. In 1818, Jackson and Kentucky governor Isaac Shelby reached an agreement with the Chickasaw to sell the land between the Mississippi and Tennessee Rivers to the United States, which included all of West Tennessee and became known as the "Jackson Purchase". The Cherokee moved their capital from Georgia to the Red Clay Council Grounds in southeastern Tennessee in 1832, due to new laws forcing them from their previous capital at New Echota. In 1838 and 1839, U.S. troops forcibly removed thousands of Cherokees and their black slaves from their homes in southeastern Tennessee and forced them to march to Indian Territory in modern-day Oklahoma. This event is known as the Trail of Tears, and an estimated 4,000 died along the way. As settlers pushed west of the Cumberland Plateau, a slavery-based agrarian economy took hold in these regions. Cotton planters used extensive slave labor on large plantation complexes in West Tennessee's fertile and flat terrain after the Jackson Purchase. Cotton also took hold in the Nashville Basin during this time. Entrepreneurs such as Montgomery Bell used slaves in the production of iron in the Western Highland Rim, and slaves also cultivated such crops as tobacco and corn throughout the Highland Rim. East Tennessee's geography did not allow for large plantations as in the middle and western parts of the state, and as a result, slavery became increasingly rare in the region. A strong abolition movement developed in East Tennessee, beginning as early as 1797, and in 1819, Elihu Embree of Jonesborough began publishing the Manumission Intelligencier (later The Emancipator), the nation's first exclusively anti-slavery newspaper. Civil War At the onset of the American Civil War, most Middle and West Tennesseans favored efforts to preserve their slavery-based economies, but many Middle Tennesseans were initially skeptical of secession. In East Tennessee, most people favored remaining in the Union. In 1860, slaves composed about 25% of Tennessee's population, the lowest share among the states that joined the Confederacy. Tennessee provided more Union troops than any other Confederate state, and the second-highest number of Confederate troops, behind Virginia.