John Brown (May 9, 1800 – December 2, 1859) was an American abolitionist who believed armed insurrection was the only way to overthrow the institution of slavery in the United States. During the 1856 conflict in Kansas, Brown commanded forces at the Battle of Black Jack and the Battle of Osawatomie. Brown’s followers killed five slavery supporters at Pottawatomie. In 1859, Brown led an unsuccessful raid on the federal armory at Harpers Ferry that ended with the multi-racial group’s capture. Brown’s trial resulted in his conviction and a sentence of death by hanging. John Brown’s attempt in 1859 to start a liberation movement among enslaved African Americans in Harpers Ferry, Virginia (later part of West Virginia), electrified the nation. He was tried for treason against the Commonwealth of Virginia, the murder of five men and inciting a slave insurrection. He was found guilty on all counts and was hanged. Southerners alleged that his rebellion was the tip of the abolitionist iceberg and represented the wishes of the Republican Party to end slavery. Historians agree that the Harpers Ferry raid in 1859 escalated tensions that, a year later, led to secession and the American Civil War.

John Brown first gained attention when he led small groups of volunteers during the Bleeding Kansas crisis. Unlike most other Northerners, who advocated peaceful resistance to the pro-slavery faction, Brown believed that peaceful resistance was shown to be ineffective and that the only way to defeat the oppressive system of slavery was through violent insurrection. He believed he was the instrument of God’s wrath in punishing men for the sin of owning slaves. Dissatisfied with the pacifism encouraged by the organized abolitionist movement, he said, “These men are all talk. What we need is action—action!” During the Kansas campaign, he and his supporters killed five pro-slavery supporters in what became known as the Pottawatomie massacre in May 1856 in response to the sacking of Lawrence, Kansas by pro-slavery forces. In 1859 he led a raid on the federal armory at Harpers Ferry. During the raid, he seized the armory; seven people were killed, and ten or more were injured. He intended to arm slaves with weapons from the arsenal, but the attack failed. Within 36 hours, Brown’s men had fled or been killed or captured by local pro-slavery farmers, militiamen, and U.S. Marines led by Robert E. Lee. Brown’s subsequent capture by federal forces seized the nation’s attention, as Southerners feared it was just the first of many Northern plots to cause a slave rebellion that might endanger their lives, while Republicans dismissed the notion and claimed they would not interfere with slavery in the South.

Historians agree John Brown played a major role in the start of the Civil War. Historian David Potter has said the emotional effect of Brown’s raid was greater than the philosophical effect of the Lincoln–Douglas debates, and that his raid revealed a deep division between North and South. Some writers, including Bruce Olds, describe him as a monomaniacal zealot; others, such as Stephen B. Oates, regard him as “one of the most perceptive human beings of his generation.” David S. Reynolds hails him as the man who “killed slavery, sparked the civil war, and seeded civil rights” and Richard Owen Boyer emphasizes that Brown was “an American who gave his life that millions of other Americans might be free.” The song John Brown’s Body made him a martyr and was a popular Union marching song during the Civil War. John Brown’s actions prior to the Civil War as an abolitionist, and the tactics he chose, still make him a controversial figure today. He is sometimes memorialized as a heroic martyr and a visionary, and sometimes vilified as a madman and a terrorist.