Since the king of Quang Nam, Nguyen Phuc Anh, established the Nguyen Dynasty with the help of the French, the Rulers of Vietnam have been struggling to survive in the cracks, and Nguyen Phuc Anh himself has explained to his descendants that he must treat the French with gratitude and without a defensive heart. His son, emperor Nguyen Phuc Huong, was primarily the embodiment of the latter, and through his measures against Catholicism, gratitude to the French was "rare" in terms of his measures against Catholicism. The French were also embarrassed and angry, and gradually stepped up the pace of expansion in the Indochina Peninsula.
During the Taiping Heavenly Kingdom Movement, Liu Yongfu joined the Heaven and Earth Society, which was regarded as a peripheral organization of the Taiping Heavenly Kingdom Movement, effectively cooperating with the Taiping Heavenly Kingdom Movement in the Liangguang region, and Liu Yongfu also grew into a small leader in the struggle.
In 1865, Liu Yongfu led his Black Flag Army to retreat into Vietnam from Guangxi, and in order to avoid the qing army, he established a foothold in the weaker northern Vietnamese and fought against various forces.
At this time, Liu Yongfu had a good impression in the eyes of the Vietnamese government, the northern Part of Vietnam was lined with mountains, And Liu Yongfu's ministry was also a force of foreign soldiers and bandits who were divided, and the Nguyen Dynasty hated that they could not be wiped out all, but suffered from the lack of troops, so they had to adopt a policy of dividing and dissolving them, provoking the masses to fight the masses.
The French forces also gradually penetrated deeper into the northern Yue region, and the Qing government saw the intention of the French, in order to prevent the French from continuing to go north, not to let the vassal state of the Nguyen Dynasty all depend on France, but also started the idea of Liu Yongfu's ministry, followed the Nguyen Dynasty to learn, and divided the Chinese forces in northern Vietnam to recruit security, and gave Liu Yongfu the official identity.
Liu Yongfu, who held the position of northern Vietnam and had the status of a dual official, began to exert his power, and successively shined in battles such as paper bridge against the French, winning the respect of his double superiors.
In the Sino-French War, the Qing army sent a Vietnamese expeditionary force to fight side by side with Liu Yongfu's troops and the Vietnamese army, winning and losing each other, Liu Yongfu also fought several victories, but the poor equipment was the weakness of the Black Flag Army, so it suffered heavy casualties.
Rao was so, compared with the weakness of the Vietnamese army, the Black Flag Army still played a demeanor, and Liu Yongfu was also the chief officer in charge of the military affairs of the Northern Yue Front, married to one of the sixty-four daughters of the Ming Emperor Nguyen Phuc, and the governor of the Northern Qi, Huang Zuoyan, who publicly evaluated it as: The Great Wall of the North!
Although it is said on the surface, in fact, Huang Zuoyan and Liu Yongfu's private relationship is the same as the water and fire, Huang Zuoyan's military merits to Liu Yongfu are mostly hidden and unreported, and Liu Yongfu simply does not listen to Huang Zuoyan's dispatch and command, and dismantles each other.
For the Vietnamese people, they themselves are also seriously divided, some follow the Xianyi Emperor Nguyen Phuc Minh and Zun Mu chambers to engage in the Qinwang movement, and some give the French the French the way of treachery, for the former, Liu Yongfu's black flag army is of course an object that can be jointly used and a tool to attract wolves and drive away tigers; for the latter, Liu Yongfu's black flag army is naturally a typical representative of the corrupt Qing government's evil old forces, and is an evil and disturbing dark force.