After the Civil War, many states passed a series of related laws known as Black Codes. Passed in 1865 and 1866, these laws represented efforts by whites to establish what freedom and citizenship for African Americans meant. The Black Code of Mississippi was the first and most extreme example and made clear that freedom for Blacks was to differ very little from enslavement. The laws exemplify the attitudes of whites toward African Americans. One of things the Mississippi Black Code shows is that African Americans were powerless in the immediate aftermath of the Civil War. Without assistance, African Americans were vulnerable to white backlash in the South. The passing of the Mississippi Black Code led to the intervention of Congress to insist on a more radical approach to Reconstruction than was called for by President Andrew Johnson. A year after the passage of the Mississippi Black Code, Congress assumed authority over Reconstruction in the southern states.