From 1885 to 1908, many atrocities were committed in the Congo Free State (today the Democratic Republic of the Congo) under the absolute rule of King Leopold II of Belgium. These atrocities were particularly associated with the labour policies, enforced by colonial administrators, used to collect natural rubber for export. Combined with epidemic disease, famine, mass population displacement and, falling birth rates caused by these disruptions, the atrocities contributed to a sharp decline in the Congolese population. The magnitude of the population decline over the period is disputed, with modern estimates ranging from 1.2 million to 10 million.
At the Berlin Conference of 1884–1885, the European powers recognized the claims of a supposedly philanthropic organisation run by Leopold II, to most of the Congo Basin region. Leopold had long-held ambitions for colonial expansion. The territory under Leopold's control exceeded 2,600,000 km (1,000,000 sq mi), more than 85 times the territory of Belgium; amid financial problems, it was directed by a tiny cadre of administrators drawn from across Europe. Initially the quasi-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 vacant 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 free rein to exploit the concessions, with the result being that forced labour and violent coercion were used to collect the rubber cheaply and maximise profit. The Free State's military force, the Force Publique, enforced the labour policies. Individual workers who refused to participate in rubber collection could be killed and entire villages razed.