Late in 1857 he began to enlist men for a project that he apparently had considered for some time and that took definite form at a convention of his followers held at Chatham, Ont., the next spring. He planned to liberate the slaves through armed intervention by establishing a stronghold in the Southern mountains to which the slaves and free blacks could flee and from which further insurrections could be stirred up. Early in 1859, Brown rented a farm near Harpers Ferry, Va. (now W.Va.), and there collected his followers and a cache of arms.
On the night of Oct. 16 he, two of his sons, and 19 other followers crossed the Potomac and without much resistance captured the U.S. arsenal at Harpers Ferry, made the inhabitants prisoners, and took general possession of the town. Strangely enough, he then merely settled down, while the aroused local militia blocked his escape. That night a company of U.S. marines, commanded by Col. Robert E. Lee, arrived, and in the morning they assaulted the engine house of the armory into which Brown's force had retired. In the resulting battle, 10 of Brown's men were killed, and Brown himself was wounded. News of the raid aroused wild fears in the South and came as a great shock to the North. On Dec. 2, 1859, Brown was hanged at Charles Town. His dignified conduct and the sincerity of his calm defense during the trial won him sympathy in the North and led him to be widely regarded as a martyr.
The standard contemporary account is contained in The Life, Trial and Execution of Captain John Brown (1859, repr. 1969). See also biographies by O. G. Villard (rev. ed. 1965), S. B. Oakes (1970), J. Abels (1971), and D. S. Reynolds (2005); A. Keller, Thunder at Harper's Ferry (1958); J. C. Malin, John Brown and the Legend of Fifty-Six (1942, repr. 1970); R. O. Boyer, The Legend of John Brown (1973); J. Stauffer, The Black Hearts of Men (2002); F. Nudelman, John Brown's Body (2004).