Violent incidents occurred throughout the Piedmont of the state as white insurgents struggled to maintain white supremacy in the face of social changes after the war and granting of citizenship to freedmen by federal constitutional amendments. After former Confederates were allowed to vote again, election campaigns from 1872 on were marked by violent intimidation of blacks and Republicans by white Democratic paramilitary groups, known as the Red Shirts.
What granted Freeman were American citizenship?
federal constitutional amendments.