The Antebellum Age was a period of increasing division in the country based on the growth of slavery in the American South and in the western territories of Kansas and Nebraska that eventually lead to the Civil War in 1861. The Antebellum Period is often considered to have begun with the Kansas–Nebraska Act of 1854,[citation needed] although it may have begun as early as 1812. This period is also significant because it marked the transition of American manufacturing to the industrial revolution.[citation needed]