Soldiering Freedmen are a small part of the novel because they didn’t fight in the Battle of Fort Sanders, but were only on garrison guard duty. Particularly around the Knoxville jail, Castle Fox, which held some Confederate prisoners.
But whereas the U.S. Colored Troops were controversial in some parts of the North and certainly most places in the South, there was apparently good feeling for them in parts of East Tennessee, as related in this 1888 history of their part in the war. When Union army officials sought in 1864 to raise a black regiment of heavy artillery from the Knoxville-Chattanooga area, they found ready support among white Union troops:
“The officers and men of the Ninth Artillery Corps,” wrote Lieutenant Colonel Thomas J. Morgan, of the Fourteenth United States Colored Troops stationed at Galatin, TN, “look with favor upon it and many excellent men are asking positions in the regiments now being formed. Commissioned officers of old regiments are asking to be transferred with same rank from white regiments to the black ones.”
Via Civil War Memory.