The Reconstruction era, often simply called Reconstruction, was a period in United States history that followed the American Civil War (1861–1865) and was dominated by the legal, social, and political challenges of the abolition of slavery and federal control over, and reintegration of, the former Confederate States into the United States. Three amendments were added to the United States Constitution to grant citizenship and equal civil rights to the newly freed slaves. To circumvent these, former Confederate states imposed poll taxes and literacy tests and sought to intimidate and control the Black population and discourage or prevent them from voting.