During the American Civil War, Cincinnati played a key role as a major source of supplies and troops for the Union Army. It also served as the headquarters for much of the war for the Department of the Ohio, which was charged with the defense of the region, as well as directing the army's offensive into Kentucky and Tennessee. Due to Cincinnati's commerce with slave states and history of settlement by southerners from eastern states, many people in the area were "Southern sympathizers". Some participated in the Copperhead movement in Ohio