While it has always been known that the song was written during American slavery and that when those words about this nation being the "land of the free" didn't apply to the millions who had been held in bondage, few of us had any idea that the song itself was rooted in the celebration of slavery and the murder of Africans in America, who were being hired by the British military to give them strength not only in the War of 1812, but in the Battle of Fort McHenry of 1814. These black men were called the Corps of Colonial Marines and they served valiantly for the British military. Key despised them. He was glad to see them experience terror and death in war — to the point that he wrote a poem about it. That poem is now our national anthem.