The historical movement defined by the conflict between Northern and Southern states over slavery is the American Civil War, which lasted from 1861 to 1865. The war arose primarily from tensions surrounding slavery, states' rights, and economic differences. The Southern states, heavily reliant on agriculture and enslaved labor, sought to preserve their way of life, while the Northern states favored abolition and a more industrialized economy. The conflict ultimately led to a bloody and devastating war that resulted in the preservation of the Union and the end of slavery, shaping the course of American history and influencing civil rights movements in the following centuries.