Most of the first African Americans were brought to North America as part of the Atlantic slave trade. African slaves were brought to North America from 1619 to 1808. After the United States became independent, slavery became illegal in most northern states. At the same time, slavery grew more important to the economy of the southern states. Many African American slaves worked on plantations (large farms) that grew cotton and tobacco. Plantation work was very difficult and slaves were often whipped and physically punished. It was illegal for slaves to learn how to read and write. White men often raped slave women, but were not punished.