In the mid 1800s, the struggle over slavery polarized the U.S. and turned Kansas Territory into a battleground after the Kansas-Nebraska Act of 1854 let its voters decide whether it would be free or slave. Antislavery and proslavery settlers flooded in, violence claimed at least 50 lives during the territorial period, and the conflict became known as Bleeding Kansas. Abolitionist John Brown became a national figure in this turmoil, leading the Pottawatomie Massacre and continuing attacks on proslavery farms in Missouri while freeing slaves through the Underground Railroad. On the morning of May 19, 1858, Charles Hamilton led 20 to 30 proslavery horsemen to Trading Post, where they captured 11 unarmed antislavery men between there and this place, marched them toward the border, and lined them up in a ravine. From the ledge above, Hamilton ordered his men to fire, then dismounted to finish the job; five captives died, five were wounded, and one survived by pretending to be dead. Sarah Read, searching for her husband, the Reverend B. L. Read, followed the trail nearly two miles, heard the gunshots, confronted some of Hamilton's men, found the victims in the ravine, and returned with the wives of two other victims to bring aid. The killings drew national attention, were denounced even by some proslavery editors, and intensified sectional tensions. Nineteen months later the governor signed an act prohibiting slavery in Kansas Territory, and on January 29, 1861, Kansas entered the United States as the 34th state, a free state.