During the Reconstruction era after the Civil War, the U.S. Congress passed four Civil Rights Acts, on April 9, 1866; May 31, 1870; April 20, 1871; and March 1, 1875. The third is also known as the Ku Klux Klan (KKK) Act. Collectively, these acts are sometimes called Enforcement Acts, for they were intended to create a more just and racially inclusive American culture by enforcing the Fourteenth and Fifteenth Amendments to the U.S. Constitution, which, together with the Thirteenth Amendment abolishing slavery, are often called the Reconstruction Amendments. While the Civil Rights Acts all shaped and protected the Fourteenth and Fifteenth Amendments, the KKK Act specifi cally aimed at violence and conspiracies perpetrated against black Americans.