The core issue of, or reason for, the civil war was over slavery. Several southern states succeeded from the rest of the USA and called themselves the Confederate States of America. These states were known as the South and the rest of the states were known as the North. After four years of war, the North won the war by destroying much of the South. They then proceeded to plunder what was known as the Wild West and harassed the African American tribes even though the African Americans were not involved in the civil war.
