By Indochina here is meant the three countries now known as Cambodia, Laos and Vietnam which, together with Burma, Thailand and Malaya, form the eastern most region of the Indochinese peninsula. Culturally and religiously, all these countries have been influenced by both India and China. In 1859, France captured the three south-eastern provinces of Vietnam, and in 1862 turned them into its colony and named it Cochin china. In 1883, France made the northern and central parts of Vietnam (Tonkin and Annam respectively) into its protectorates. In 1887, it merged Vietnam with Cambodia to form the Union of French Indochina, to which Laos was added in 1893. In addition to politics which bound these three countries together, their Christian churches are so deeply intertwined, with Vietnam often sending missionaries into the other two countries, that a joint treatment of their Christian histories is appropriate.

Christianity in Vietnam, 1815–1915: a century of bloodshed and growth

The century of Vietnamese Christianity under consideration falls within the rule of the Nguyen dynasty (1802–1945) at whose hands it suffered the longest and bloodiest persecutions. Moreover, it was during the Nguyen dynasty that France colonised Vietnam, and its rule, which began in 1862, lasted until 1954. Hence, this period of the history of Vietnamese Christianity also partially overlaps with the history of French colonisation of Vietnam and must be considered in relation to it.