As the Second World War spread across Europe, France was conquered by Nazi Germany in June 1940. Three months later, Japanese forces occupied Indochina with the cooperation of the French Vichy government. With the displacement of France's brutal colonial regime, several nationalist and communist organizations quickly formed to resist the Japanese occupation. The largest of these was the Vietnam Doc-Lap Dong Minh Hoi, or Viet Minh, led by Ho Chi Minh.
After the war ended in 1945, France attempted to reassert control in the region. But the Viet Minh quickly seized local control in most of Indochina, and declared an independent country, the Democratic Republic of Vietnam. Negotiations between France and the Viet Minh failed, and nine years of war followed. While France (with financing from the United States) had overwhelming superiority in weaponry, the Viet Minh was able to compensate through sheer force of numbers, recruiting guerrilla fighters from the local peasant population. The communist takeover of China in 1949 provided the Viet Minh with an important ally, and by the middle of 1954 France realized that the war could not be won. An international conference held in Geneva in July 1954 called for an armistice, free elections within two years, and a temporary partitioning of the country at the seventeenth parallel.