On 16 October 1856 he led a group of 20 men in a raid of an arsenal. They attacked and captured several buildings. His revolt was defeated by U.S. Marines.
John Brown was tried for treason, convicted and hanged. Brown was allowed make an address to the court: "Now, if it be deemed necessary that I should forfeit my life for the furtherance of the ends of justice, and mingle my blood further with the blood of my children, and with the blood of millions in this slave country whose rights are disregarded by wicked, cruel, and unjust enactments, I submit: so let it be done."
Although John Brown's revolt failed, it set the stage for a much larger confrontation regarding slavery: the Civil War.