The major events in the nineteenth century

Considering the nineteenth century, it seems clear that the major event was the Civil War. The controversies before the War, the War itself and the direction of the country after the War were all determined by the multiple political, social, economic and cultural issues or activities of the period--religious revivalism, reform movements, regionalism, slavery, the erosion of the frontier-- are but a few of the possibilities. Pick one such issue or activity of some importance and duration and trace its history. Also, include the important ways this thread or theme impacted other, related developments.