Cochinchina campaign

From 1858 to 1862 French and Spanish forces fought a war against the Vietnamese empire of the Nguyễn emperor Tự Đức, then known as Đại Nam. What began as a punishment for the execution of Catholic missionaries grew into a war of conquest that ended with the Treaty of Saigon and the cession of three southern provinces to France. The campaign opened the French conquest of Vietnam, which led in time to French rule over all of Indochina.

French Catholic missionaries had worked in Vietnam since the seventeenth century, and by the mid-nineteenth century, according to one French bishop, there were some 600,000 Vietnamese Catholics in the centre and north. Many Vietnamese distrusted this community and its foreign clergy, and the emperors Minh Mạng and Thiệu Trị harassed and persecuted missionaries, drawing only scattered French responses. In 1857 Tự Đức sanctioned the killing of two Spanish missionaries. France already had forces in the region for the Second Opium War in China, and in November 1857 Napoleon III gave Admiral Charles Rigault de Genouilly command of a punitive expedition.

In September 1858 a Franco-Spanish force landed at Tourane, today's Da Nang, and took the town. The quick success the allies expected did not follow. Vietnamese Catholics did not rise in support, as a French bishop had predicted, and an army under Nguyễn Tri Phương hemmed the invaders in. The siege of Tourane dragged on for nearly three years; there was little fighting, but disease killed many French and Spanish soldiers. Rigault de Genouilly decided to strike instead at Saigon, an important source of rice for the Vietnamese army.

On 17 February 1859 the allies forced their way up the Saigon river and captured the city and its large citadel, with Filipino troops under Spanish command beating off a counter-attack. Lacking men to hold the citadel, they blew it up in March and burned the rice stores. France was then distracted by war in Italy and again in China, and a garrison of about 1,000 men was left to hold Saigon, where a Vietnamese army besieged it from March 1860 to February 1861. Unable to hold both positions, the French abandoned Tourane in March 1860.

With the China war over, Admiral Léonard Charner brought a fleet of 70 ships and 3,500 soldiers south. On 24 and 25 February 1861 the allies stormed the Vietnamese siege lines at Ky Hoa, defeating Nguyễn Tri Phương at considerable cost. Mỹ Tho fell without a fight on 12 April. Shortly before, France had demanded the cession of territory, an indemnity and freedom of trade, which Tự Đức refused. He turned to guerrilla resistance, and French troops responded with a harshness that fed further revolt. In a separate incident on 31 July 1861 the American warship USS Saginaw, fired on while searching for missing sailors, destroyed the fort at Qui Nhơn. Admiral Louis Bonard, Charner's successor, took Biên Hòa on 16 December 1861 and Vĩnh Long in March 1862.

Facing these losses and a major revolt in Tonkin under Le Bao Phung, a Catholic claiming descent from the old Lê dynasty, Tự Đức sought peace in April 1862. On 5 June 1862 his minister Phan Thanh Giản signed the Treaty of Saigon. Vietnam agreed to allow Catholic worship, to cede the provinces of Biên Hòa, Gia Định and Định Tường and the Poulo Condore islands to France, to let the French trade on the Mekong, to open three ports, and to pay an indemnity of one million dollars to France and Spain over ten years.

The ceded provinces became the French colony of Cochinchina, with Saigon as its capital. In 1867 France seized three more provinces, a loss Tự Đức eventually accepted in a second Treaty of Saigon in 1874. The Spanish Empire, which had played the junior role with troops drawn partly from the Philippines, received part of the indemnity but no territory, and kept only a small force in Saigon until 1863. Tonkin became a French protectorate in 1883.

Our 1815 map shows Vietnam before the French intervention, and our 1900 map shows the region as part of French Indochina.