William Henry Sheppard was one of the earliest African Americans to become a missionary for the Presbyterian Church. He spent 20 years in Africa, primarily in and around the Congo Free State, and is best known for his efforts to publicize the atrocities committed against the Kuba and other Congolese peoples by King Leopold II's Force Publique.

The Zappo Zaps were a group of Songye people from the eastern Kasaï region in what today is the Democratic Republic of the Congo. They acted as allies of the Congo Free State authorities, while trading in ivory, rubber and slaves. In 1899 they were sent out by the colonial administration to collect taxes. They massacred many villagers, causing an international outcry.