The fighting in Kansas territory between pro- and antislavery settlers and others in the mid-1850s foreshadowed the US Civil War that was to come in 1861. On May 21, 1856, a group of proslavery "border ruffians," armed thugs from Missouri, raided the town of Lawrence, Kansas, buring and destroying buildings owned by free-soilers (those opposed to slavery in the western territories). A fanatical American abolitionist named John Brown (1800-59), who had come to Osawatomie, Kansas, to join his sons in 1855 and to help the antislavery forces there, was enraged by the "sack of Lawrence" and decided to take revenge. On the night of May 24-25, 1856, he and six of his followers, including four of his sons, dragged five men from their cabins in a proslavery settlement at Pottawatomie Creek, Franklin County, Kansas, and one by one and in cold blodd, hacked them to death. This "massacre" helped greatly to fuel the sporadic guerrilla border war in "bleeding Kansas." Federal troops finally had to intervene to stop the bloodshed and lawlessness. By the time Kansas entered the Union as a free (nonslave) state in 1861 more than 200 persons had been killed in clashes.