Under Nguyen dynasty, Vietnam economy, politics, society developed very slowly, the way of thinking, of living of ancient Chinese dynasties had been maintained as pattern for King and his Court to decide any behavior.
Nguyen Emperors refused any idea to reform after the West countries or Japan ignored any affection from outside in science, technology, culture or thinking. At the end of the 19th century, in Vietnam, the intellectuals still didn't know mathematics, physics, and chimes. Just studied Confucianism, and wrote poems on nature or praise the King's wisdom.
In 1858,France started their plan of invading Vietnam step by step. With the poor economy and an out-of-date army, Nguyen Dynasty couldn't resist against the French military force and had to make a number of concessions one after another.
1860-1900: Popular armed struggle against the French patriotic Can Vuong (serve the King) movement led by Confucian scholars ( Phan Dinh Phung, Nguyen Thien Thuat, Only Hoang Hoa Tham held out until 1913)
In 1883, Vietnam's independence ended with the domination of France. The French divided Vietnam into two parts: the Cochinchina as a colony, and the central and north as protectorate territories.
Under French domination, Nguyen Emperors were like puppets with no real power. Some of them: Ham Nghi, Thanh Thai,Dzuy Tan had the idea or even waged the resistance against the French, but they all soon failed.
1904-1925: Patriotic and renovation movements led by modernist scholars ( Phan Boi Chau, Phan Chu Trinh..)
1925: Great workers' strikes. Foundation of the Viet Nam Revolutionary Youth Association.
Feb/1930: Failure of the nationalist (Nguyen Thai Hoc)Viet Nam Quoc Dan Dang's insurrection
The society and economy of Vietnam from that time developed in Western way. Everything changed, from the Vietnamese letters (before, the Chinese had been used as official letters), to the way of living. Vietnamese intellectuals now found them facing with science, technology, thinking of the West. A real revolution in all aspects happened in Vietnam society that time.
But, the French colonialism also exposed its harshness on Vietnamese that most were peasants: the exploitation of labors and natural sources, the abuse of authority, the violation of human rights, the poverty, the breaking traditional social society...etc, were consequences.
From the time of the first invasion battle of France, a movement of Vietnamese nationalism had risen and the French, for almost one-century had faced with a seething violence against and confrontations with the colonial authority. Many rebellions broke out; from the led-by former mandarins of Nguyen to the new West style political party led movements. The most successful, of course addressed itself to the peasantry and their grievances - fairer land distribution and release from poverty. The history of this peasant-based movement, which would eventually be known as Vietnam Communist Party, was synonymous with its leader, Ho Chi Minh. Ho's party, in 40's created League for the independence of Vietnam (Viet Minh)- a coalition of nationalist, dominated by communists - to resist the Japanese innovation and their occupation of Vietnam in early days of World War II.
By August 1945, exploited a perfect opportunity of defeat of Japanese, Ho instigated the August Revolution, assuming complete control in northern and central Vietnam.
On September, 2,1945, Ho declared the new Democratic Republic of Vietnam in Hanoi. The last dynasty of Nguyen ended.
On September, 23rd, 1945: French reconquest Of South Vietnam (Cochinchina)
19 Dec. 1946: Beginning of nation-wide resistance against the French (Later back by the USA).
October 1950: Big victory of popular forces at the Sino-Vietnamese frontier
7th May 1954: Dien Bien Phu Victory (The French forces capitulated)