Setting the scene
John Brown's raid on Harpers Ferry occurred October 16-18, 1859, when the radical abolitionist led 21 men (16 white, 5 Black) in an attack on the federal armory at Harpers Ferry, Virginia (now West Virginia). Brown, who had gained notoriety in 'Bleeding Kansas' for killing pro-slavery settlers, planned to seize weapons and spark a slave insurrection across the South. He believed that by arming enslaved people, he could create a mountain stronghold from which to wage war against slavery.
What happened
Brown's men captured the armory and rifle works on the night of October 16, taking hostages including Lewis Washington, great-grandnephew of George Washington. However, Brown failed to escape and allowed a train to pass, which alerted authorities. Local militia surrounded the raiders, and on October 17, U.S. Marines under Colonel Robert E. Lee (with Lieutenant J.E.B. Stuart) stormed the engine house where Brown had barricaded himself. Ten raiders were killed, including two of Brown's sons, and Brown was captured.
Why it still matters
Brown was tried for treason against Virginia, murder, and inciting insurrection, convicted, and hanged on December 2, 1859. His trial and execution made him a martyr in the North and a terrorist in the South. Ralph Waldo Emerson called him a saint, while Southerners saw the raid as proof of Northern intent to destroy slavery by force. The raid intensified sectional tensions, making compromise impossible and accelerating the path to Civil War. Brown's actions demonstrated that the slavery issue could no longer be resolved politically, only violently.
Background
Southern fears of slave revolt intensified.