The first African slaves to come to an American colony were actually indentured servants. Indentured servants were usually colonists who had agreed to work for a master (perhaps for several years). In exchange, the master or person holding the indenture, would pay for the colonists passage to the new world.
The 20 Africans that came to Jamestown in 1619 AD were dropped off by a Dutch fighting vessel called a man of war. At that time, the Africans and Europeans began working together in the fields.
Sometimes an indentured servant, either white or black, would run away and try to get freedom. If they were caught, the white person would be made to work additional years of bondage. However, because of the difference in skin color, black people were sentenced to a lifetime of bondage and became slaves.
This injustice, led to the rise of slavery in America and the formation of what was called the Peculiar Institution. When the Dutch dropped off the 20 Africans, slavery began in the American colonies. The Peculiar Institution would last for 247 years.
Only one other injustice could possibly compare to the treatment of black people in the first centuries of the United States. That other injustice would be the treatment of the American Indian.