Treaty of Saigon
The French invasion of Indochina was sparked off by the execution of Christian missionaries. With the defeat of Vietnamese Emperor Tự Đức signed the Treaty of Saigon, ceding Cochinchina's three eastern provinces. Later, the French forced the Emperor to place Cambodia under French protection. On June 18, 1867, the French seized the rest of Cochinchina and conquered the Mekong Delta and later Hanoi. By 1887, France controlled all of Indochina.