The violent period following the passage of the Kansas-Nebraska Act is called Bleeding Kansas. Pro-slavery Missourians rushed in to claim land and push for the state to become a slave state. Free-Staters and abolitionists poured into Kansas from New England, Ohio, Iowa, and other midwestern states. In a short time they outnumbered the pro-slavery faction. However, when elections were held in Kansas Territory, bands of armed Ruffians seized polling places. They prevented Free-State men from voting, and they cast illegal votes. There was violence on both sides. Border Ruffians also engaged in general violence against Free-State settlements. They burned farms and sometimes murdered Free-State men. Ruffians twice attacked Lawrence, Kansas, the Free-State capital. On 1 December 1855, a small army of mainly Border Ruffians laid siege to Lawrence, but were driven off. (This was the nearly bloodless climax to the "Wakarusa War".) On 21 May 1856, an even larger force of Border Ruffians and pro-slavery Kansans captured Lawrence, which they sacked. In retaliation, John Brown and 7 followers committed the Pottawatomie massacre. In this incident, Brown and his followers dragged five unarmedmen and boys from their houses and murdered with swords, guns and knives. This only increased the violence leading to the Battle of Osawatomie where the abolitionists of Osawatomie were attacked and the town burned.