How and why had blacks, particularly in the South, been subjected to second-class citizenship by 1900? Why were Jim Crow laws predominantly in the South? How did Jim Crow happen?

American Studies Question

How and why had blacks, particularly in the South, been subjected to second-class citizenship by 1900? Why were Jim Crow laws predominantly in the South? How did Jim Crow happen? Make sure you read about the Plessy case.