According to the dictionary slavery is "an institution of the common law of peoples by which a person is put into the ownership of somebody else; contrary to the natural order" slavery was commonly practiced through out ancient history. It started in Britain, and then spread all over the Europe till it reached the United States.
Before the Civil war, black people had specific stereotypical images for example; they were inferior, subhuman, weak, enslaved, ignored, hard worker, poor, and voiceless. They work as farmers, guards, housekeepers and householders.
After the Civil war slavery ended, but surprisingly these black people are still treated badly, In addition they gain different features for there stereotypical images : they became criminals, law breaker, violent, strong, rebellions, more liberal and more powerful.
I think they need long time to be equal to white people .