King Leopold II of Belgium, frustrated by Belgium's lack of international power and prestige, attempted to persuade the Belgian government to support colonial expansion around the then-largely unexplored Congo Basin.
It began almost immediately after the Congo became independent from Belgium and ended, unofficially, with the entire country under the rule of Joseph-Désiré Mobutu.
Constituting a series of civil wars, the Congo Crisis was also a proxy conflict in the Cold War in which the Soviet Union and United States supported opposing factions.
Government forces gradually retook territory and, in November 1964, Belgium and the United States intervened militarily in Stanleyville to recover hostages from Simba captivity. Following the elections in March 1965, a new political stalemate developed between Tshombe and Kasa-Vubu, forcing the government into near-paralysis.
Mobutu mounted a second coup d'état in November 1965, now taking personal control.
Under Mobutu's rule, the Congo (renamed Zaire in 1971) was transformed into a dictatorship which would endure until his deposition in 1997.
Colonial rule in the Congo began in the late 19th century.
A rival government, the Free Republic of the Congo, founded by Antoine Gizenga and Lumumba supporters in the eastern city of Stanleyville, gained Soviet support but was crushed in 1962.
Meanwhile, the UN took a more aggressive stance towards the secessionists after Hammarskjöld was killed in a plane crash in late 1961.
The Congo's rich natural resources, including uranium—much of the uranium used by the U. nuclear programme during World War II was Congolese—led to substantial interest in the region from both the Soviet Union and the United States as the Cold War developed.
An African nationalist movement developed in the Belgian Congo during the 1950s, primarily among the évolués.
With support from a number of Western countries, who viewed Leopold as a useful buffer between rival colonial powers, Leopold achieved international recognition for a personal colony, the Congo Free State, in 1885.