Originating with the birth of the nation itself, in many respects, the story of the domestic slave trade is also the story of the early United States. While an external traffic in slaves had always been present, following the American Revolution this was replaced by a far more vibrant internal trade. Most importantly, an interregional commerce in slaves developed that turned human property into one of the most valuable forms of investment in the country, second only to land. In fact, this form of property became so valuable that when threatened with its ultimate extinction in 1860, southern slave owners believed they had little alternative but to leave the Union. Therefore, while the interregional trade produced great wealth for many people, and the nation, it also helped to tear the country apart. The domestic slave trade likewise played a fundamental role in antebellum American society. Led by professional traders, who greatly resembled northern entrepreneurs, this traffic was a central component in the market revolution of the early nineteenth century.