In the period from 1885 to 1908, a number of well-documented atrocities were perpetrated in the Congo Free State (today the Democratic Republic of the Congo) which, at the time, was a colony under the personal rule of King Leopold II of Belgium. These atrocities were sometimes collectively referred to by European contemporaries as the "Congo Horrors", and were particularly associated with the labour policies used to collect natural rubber for export. Together with epidemic disease, famine, and a falling birth rate caused by these disruptions, the atrocities contributed to a sharp decline in the Congolese population. The magnitude of the population fall over the period is disputed, but it is thought to be between one and 15 million people.
At the Berlin Conference of 1884–85, the European powers allocated the Congo Basin region to a private charitable organisation run by Leopold II, who had long held ambitions for colonial expansion. The territory under Leopold's control exceeded 2,600,000 km2 (1,000,000 sq mi) and, amid financial problems, was ruled by a tiny cadre of white administrators drawn from across Europe. Initially, the colony proved unprofitable and insufficient with the state always close to bankruptcy. The boom in demand for natural rubber, which was abundant in the territory, created a radical shift in the 1890s—to facilitate the extraction and export of rubber, all "uninhabited" land in the Congo was nationalised, with the majority distributed to private companies as concessions. Some was kept by the state. Between 1891 and 1906, the companies were allowed to do whatever they wished with almost no judicial interference, the result being that forced labour and violent coercion were used to collect the rubber cheaply and maximise profit. A native paramilitary army, the Force Publique, was also created to enforce the labour policies. Individual workers who refused to participate in rubber collection could be killed and entire villages razed. Individual white administrators were also free to indulge their own sadism.