France's interest in Indochina in the nineteenth century grows out of its rivalry with Britain, which has excluded it from India and has effectively shut it out of other pans of mainland Southeast Asia.

The French also desire to establish commerce in a region that promises so much untapped wealth and to redress the Vietnamese state's persecution of Catholic converts, whose welfare is a stated aim of French overseas policy.

The Nguyen dynasty's repeated refusal to establish diplomatic relations and the violently anti-Christian policies of the emperors Minh Mang (1820-41), Thieu Tri (1841-47). and Tu Duc (1848-83) impel the French to engage in gunboat diplomacy that results, in 1862, in the establishment of French dominion over Saigon and over the three eastern provinces of the Cochinchina (Mekong Delta) region.