At the end of World War One, most black Americans were descendants of Africans who had been taken to America to be used as slaves during the 17th – 19th centuries.
They faced an unequal and segregated society in which racism and violence was common place, especially in the southern states.
Many black Americans migrated to northern cities such as New York, Detroit and Chicago, hoping to escape segregation in the south.
Competition for jobs between black people and white people soon led to an increase in racial tensions in northern cities.
Like new immigrants, black people were often used to break strikes and were blamed for lowering wages.
After the war, there were race riots in several northern cities. The worst violence occurred in Chicago in 1919 and resulted in 138 deaths with the army being used to end the violence.