John Brown was a radical abolitionist who believed armed insurrection was the only way to overthrow the institution of slavery in the United States. He gained notoriety for leading violent attacks against pro-slavery settlers in Kansas in 1856 and for his audacious raid on the federal armory at Harpers Ferry, Virginia, in 1859. While the Harpers Ferry raid failed to spark a widespread slave rebellion, it heightened tensions between the North and South, pushing the nation closer to civil war. Brown's conviction and execution for treason further polarized the country, solidifying him as a martyr for abolitionists and a symbol of dangerous extremism for slaveholders.