invitation to violence The most controversial provision in the Kansas–Nebraska Act was the stipulation that settlers in Kansas Territory would vote on whether to allow slavery within its borders. This provision repealed the Missouri Compromise of 1820, which had prohibited slavery in any new states created north of latitude 36°30'. Predictably, violence resulted between the Northerners and Southerners who rushed to settle there in order to control the vote. Within a few days after the passage of the Act, hundreds of pro-slavery Missourians crossed into the adjacent territory, selected an area of land, and then united with other Missourians in a meeting or meetings, intending to establish a pro-slavery preemption upon the entire region. As early as June 10, 1854, the Missourians held a meeting at Salt Creek Valley, a trading post three miles (5 km) west of Fort Leavenworth, at which a "Squatter's Claim Association" was organized. They said they were in favor of making Kansas a slave state, if it should require half the citizens of Missouri, musket in hand, to emigrate there, and even to sacrifice their lives in accomplishing this end. To counter this action, the Massachusetts Emigrant Aid Company (and other smaller organizations) quickly arranged to send anti-slavery settlers (known as "Free-Staters") into Kansas in 1854 and 1855. The principal towns founded by the New Englanders were Topeka, Manhattan, and Lawrence. Several Free-State men also came to Kansas Territory from Ohio, Iowa, Illinois and other Midwestern states. Bleeding Kansas Despite the proximity and opposite aims of the settlers, the lid was largely kept on the violence until the election of the Kansas Territorial legislature on March 30, 1855. On that date, Missourians who had streamed across the border (known as "Border Ruffians") filled the ballot boxes in favor of pro-slavery candidates. As a result, pro-slavery candidates prevailed at every polling district except one (the future Riley County), and the first official legislature was overwhelmingly composed of pro-slavery delegates. From 1855 to 1858, Kansas Territory experienced extensive violence and some open battles. This period, known as "Bleeding Kansas" or "the Border Wars", directly presaged the American Civil War. The major incidents of Bleeding Kansas include the Wakarusa War, the Sacking of Lawrence, the Pottawatomie massacre, the Battle of Black Jack, the Battle of Osawatomie, and the Marais des Cygnes massacre. Wakarusa War On December 1, 1855, a small army of Missourians, acting under the command of