The Republican Party was founded in the Northern states in 1854 by forces opposed to the expansion of chattel slavery, ex-Whigs, and ex-Free Soilers. The Republican Party quickly became the principal opposition to the dominant Democratic Party and the briefly popular Know Nothing Party. The party grew out of opposition to the Kansas–Nebraska Act, which repealed the Missouri Compromise and opened Kansas Territory and Nebraska Territory to chattel slavery and future admission as slave states. The Republicans called for economic and social modernization. They denounced the expansion of chattel slavery as a great evil, but did not call for ending it in the Southern states. The first public meeting of the general anti-Nebraska movement, at which the name Republican was proposed, was held on March 20, 1854 at the Little White Schoolhouse in Ripon, Wisconsin. The name was partly chosen to pay homage to Thomas Jefferson's Republican Party. The first official party convention was held on July 6, 1854 in Jackson, Michigan.