The first slave were brought in 1619 by Dutch merchants.
You can refer to the chapter "Draw the color line" in Howard Zinn's A People's History of the United States.
It was part of the triangular trade system created by Europeans.
Slavery predates the written word.
Slavery was referred to in the Book of Genesis and is not a recent feature. It did not begin with the American colonies, nor did it end with the American Civil War.