When cotton was king during the 1850s, Mississippi plantation owners—especially those in the old Natchez District, as well as the newly emerging Delta and Black Belt region of the uplands in the center of the state—became increasingly wealthy due to the great fertility of the soil and the high price of cotton on the international market. The severe wealth imbalances and the necessity of large-scale slave populations to sustain such income played a strong role in state politics and political support for secession. Mississippi was among the six states in the Deep South with the highest proportion of slave population; it was the second state to secede from the union.