The Congo Free State was a kingdom privately and controversially owned by King Leopold II of Belgium that included the entire area now known as the Democratic Republic of the Congo. Leopold II began laying the diplomatic, military, and economic groundwork for his control of the Congo in 1877, and ruled it outright from early 1885 until its annexation by Belgium in 1908.

The people of the Congo Free State suffered under King Leopold's rule. He treated the people cruelly and forced them to work long hours at such jobs as collecting rubber in forest and building a railroad. Many of the people died as a result of the harsh treatment.

In 1908, the Belgian Government took over the highly indebted, scandal-ridden Congo Free State, which was renamed Belgian Congo. A colonial charter was passed in Belgium's parliament, outlawing forced labor. BOMA continued to be the capital. The notorious rubber tax was abolished in 1912.

In 1914, World War I broke out. Belgium, despite declaring its neutrality, was invaded, and for the most part occupied by German forces in the first weeks of the war.

The Belgian Congo shared a common border with German East Africa. In 1916, Belgian forces invaded German East Africa, occupying areas in the northeast. In 1920, these areas Ruanda and Urundi (now called Rwanda and Burundi) - were given to Belgium as a mandate of the League of Nations and administrated as an annex to the Belgian Congo. Belgium was earning a great wealth from the Belgium Congo's copper; diamonds, gold, palm oil and other resources fell sharply.

Belgium entered World War II in 1940, on the side of the Allies. During the war the Belgian Congo provided the Allies with valuable raw materials. Belgium was again invaded by Germany in 1940 during the blitzkrieg offensive. After World War II, ended in 1945, Belgian Congo's economy developed rapidly as demands for export went up.

The Belgians made an effort to improve education and medical care for the people, yet refusing to give a voice in the government. The people of Belgian Congo whated their independence and in 1957, Belguim allowed the people to elect their own representatives to some city council.

In 1950s Belgium was under pressure to tranform the Belgian Congo into a self-government state. Belgium had ratified article 73 of the United Nations Charter, which advocated self-determination, and both superpowers put pressure on Belgium to reform their Congo policy. The Belgian government's response was largely dismissive. In 1955, A. J. Van Blilsen published a treatise called Thirty Year Plan for the Political Emancipation of Belgian Africa. It called for a gradual emancipation of Congo over a thirty year period, giving enough time to replace the position of power. On June 30, 1960 Belgium granted the colony independence. The new country was called Congo.