Cochinchina in the context of "Trịnh lords"

The Nguyễn dynasty (Vietnamese: Nhà Nguyễn or Triều Nguyễn, chữ Nôm: 茹阮, chữ Hán: 朝阮) was the last Vietnamese dynasty, preceded by the Nguyễn lords and ruling unified Vietnam independently from 1802 until the start of the French protectorate in 1883. Its emperors were members of the House of Nguyễn Phúc. During its existence, the Nguyễn empire expanded into modern-day Southern Vietnam, Cambodia, and Laos through a continuation of the centuries-long Nam tiến and Siamese–Vietnamese wars. With the French conquest of Vietnam, the Nguyễn dynasty was forced to give up sovereignty over parts of Southern Vietnam to France in 1862 and 1874, and after 1883 the Nguyễn dynasty only nominally ruled the French protectorates of Annam (Central Vietnam) as well as Tonkin (Northern Vietnam). Backed by Imperial Japan, in 1945 the last Nguyễn emperor Bảo Đại abolished the protectorate treaty with France and proclaimed the Empire of Vietnam for a short time until 25 August 1945.

The House of Nguyễn Phúc established control over large amounts of territory in Southern Vietnam as the Nguyễn lords (1558–1777, 1780–1802) by the 16th century before defeating the Tây Sơn dynasty and establishing their own imperial rule in the 19th century. The dynastic rule began with Gia Long ascending the throne in 1802, after ending the previous Tây Sơn dynasty. The Nguyễn dynasty was gradually absorbed by France over the course of several decades in the latter half of the 19th century, beginning with the Cochinchina Campaign in 1858 which led to the occupation of the southern area of Vietnam. A series of unequal treaties followed; the occupied territory became the French colony of Cochinchina in the 1862 Treaty of Saigon, and the 1863 Treaty of Huế gave France access to Vietnamese ports and increased control of its foreign affairs. Finally, the 1883 and 1884 Treaties of Huế divided the remaining Vietnamese territory into the protectorates of Annam and Tonkin under nominal Nguyễn Phúc rule. In 1887, Cochinchina, Annam, Tonkin, and the French Protectorate of Cambodia were grouped together to form French Indochina.

The French conquest of Vietnam (1858–1885) was a series of military expeditions that pitted the Second French Empire, later the French Third Republic, against the Vietnamese empire of Đại Nam in the mid-late 19th century. Its end results were victories for France as they defeated the Vietnamese and their Chinese allies in 1885, incorporated modern-day Vietnam, Laos, and Cambodia into the French colonial empire, and established the territory of French Indochina over Mainland Southeast Asia in 1887.

A joint Franco-Spanish expedition was initiated in 1858 by invading Tourane (modern day Da Nang) in September 1858 and Saigon five months later. This four-year campaign resulted in Emperor Tu Duc signing a treaty in June 1862, granting the French sovereignty over three provinces in the South. The French annexed the three southwestern provinces in 1867 to form Cochinchina. Having consolidated their power in Cochinchina, they conquered the rest of Vietnam through a series of campaigns in Tonkin between 1873 and 1886. French ambitions to subjugate Tonkin were opposed by the Qing dynasty, the region being part of the Chinese sphere of influence.

Southern Vietnam (Vietnamese: Nam Bộ) is one of the three geographical regions of Vietnam, the other two being Northern and Central Vietnam. It includes 2 administrative subregions, which in turn are divided into 19 First Tier units, of which 17 are provinces and 2 are municipalities.

Known as Nam Bộ today in Vietnamese, it was historically called Gia Định (1779–1832), Nam Kỳ (1832–1945, during Nguyễn's Lục tỉnh and French Cochinchina), Nam Bộ (1945 to the present, encompassing the Empire of Vietnam and the Democratic Republic of Vietnam), and Nam Phần, sometimes Nam Việt (1948–1975, during the State of Vietnam and the Republic of Vietnam). Cochinchina is a historical exonym for this region during the colonial period, which referred to the entire domain of Đàng Trong in the feudal period. A more accurate term for the southern region is Lower Cochinchina, or Basse-Cochinchine in French.