This is the day they hung John Brown for his failed raid on the federal arsenal at Harper’s Ferry.
As one history website puts it:
In the mid-1850s, abolitionist John Brown went to Kansas Territory to fight against the spread of slavery. Then in 1859, he came east to Virginia, hoping to liberate slaves. On October 16, he and a small group of militants seized the federal armory in Harper’s Ferry and its weapons, but waited in vain for the uprising they hoped would follow. The next day, U.S. Army officers Robert E. Lee and J. E. B. Stuart brought in a company of marines and stormed the fire-engine house where Brown had retreated. They captured him and his band, and killed two of his sons. Brown was hanged, along with six other conspirators. In death he became a martyr for abolitionists. “I am worth inconceivably more to hang,” he said, “than for any other purpose.”
His little band had both white and black conspirators, and significant financial support from white and black abolitionists. Still, not only did white conservatives react negatively and in the extreme to his raid after it happened, but some African American leaders also feared it would make things worse for the abolition cause — and that Brown as a white man had ignored black dissenting voices on the matter. There was much discussion over the issue of black people needing black, not white, leaders of resistance to their racial oppression.