Theorie:

In order to be able to talk about the history of African Americans, you need to study the appropriate vocabulary.
  
racial-segregation-67692_960_720.jpg   barack-obama-1129156_960_720.jpg
 
Nouns
African American = a black American of African origin / can also be used as an adjective
slavery = the act of being forced to work, bondage
slave = a person who is forced to work for somebody else
cotton = a soft, white plant used in making fabrics, pullovers, etc. (Baumwolle)
oppression = the exercise of authority or power in a cruel or unjust manner
engine = a machine producing force and movement
law = a rule in a state or nation that has to be followed by its people
 
segregation = setting apart or separating people
racial segregation = black people were separated from white people earlier in the U.S.
 
Adjectives
fugitive = having taken flight, or run away
profitable = to be able to earn money with sth.
slave-holding = a person holding slaves, also: a state legalizing the holding of slaves
constitutional = not prohibited by the constitution, legal =/ unconstitutional
equal = to be the same as, to be of the same rank =/ unequal
  
Verbs
to secede = to separate oneself from sth., to withdraw from an alliance, association, etc.
to restrict = to keep within limits
to be forced to do sth. = to do sth. involuntarily, to do sth. although a person does not want to do it
to be assassinated = to be attacked physically, often to be killed as a consequence
to require = to have need of
 
Examples:
Slavery was abolished in the U.S. in 1865.
Many slaves suffered from the oppression of their masters.
Racial segregation was a major problem in the U.S. in the preceding century.
There were a lot of fugitive slaves escaping from their masters.
Growing cotton was very profitable.
Nowadays, African Americans should be equal to white people.