In 1879, King Leopold II of Belgium founded the International Association of the Congo to further his interests in the region. By the time he assumed personal control of the Congo Free State in 1885, he had managed to convince both the Belgian Parliament and the other European powers that his interest in the Congo was humanitarian rather than political or financial. He did this partly by employing the well-known journalist and explorer Henry Morton Stanley, financing Stanley's African expeditions for a period of five years. Stanley's involvement persuaded Britain and the other European powers that Leopold's mission was to civilize the Congo, rather than to exploit it.

Over the next twenty years, the Congo Free State became notorious for the cruelty with which it was governed. The publication of Joseph Conrad's novel Heart of Darkness in 1899 added to the outcry, and missionaries in Africa complained of murders and mutilations in King Leopold's domain. The Congo Reform Association was founded in 1904, by which time the Congo Free State had become an international embarrassment to Belgium. The Belgian Parliament was initially reluctant to take over the running of the state, and ended up having elections to resolve the issue. These proved decisive and, after two years of political wrangling over the matter, the Belgian Congo was established as a national parliamentary colony on November 15, 1908.