how did French established their control over Vietnam??
Answers
The Catholics spent a lot of time creating indigenous Priesthood after their experience in Japan where foreign Priests were easy targets for suppression.
The Vietnamese Government in Hue signed a Treaty with France in 1787 but it achieved limited results. Changes in the Vietnamese government turned against the French and the Catholic Missionaries.
France began to take an interest in China after the First Opium War. The French Strategy was to create a base in South-East Asia and open trade with China through the South. They also wanted to stop the persecution of Catholics in Vietnam. Using a fleet of ships and troops the French destroyed Vietnamese naval and land forces.
They created a colonial state, Cochin China, in the Cambodia/South Vietnam area by 1864. The French slowly expanded, defeating both Chinese and Vietnamese forces till they were in possession of all the area that is now Vietnam, Cambodia and Laos by 1887. This area was recognized as a French Colony by China.