[9] In 1782, the Tây Sơn attacked Gia Định (later known as Saigon and now Ho Chi Minh City) again and forced Nguyễn Ánh to flee to the island of Phú Quốc under Duyệt's escort.

Continuous warfare then ensued, mostly centred near Nha Trang and Qui Nhơn on the south central coast, where the Nguyễn besieged the Tây Sơn's strongholds.

[15] Lê Văn Duyệt and his deputy Le Chat then defeated the Tây Sơn army and forced their commander, Prince Consort Nguyen Van Tri, to flee.

[19] He also tried to expand the support base for the Nguyễn in the south by appointing newly arrived Chinese refugees who had fled their homeland after the fall of the Ming dynasty as well as former rebels and bandits, to administrative posts if they were qualified, and encouraging their integration into and participation in society.

He reinstated Ang Chan and built two citadels, Nam Vang and La Liem[n 4] on Cambodian territory in order to maintain Vietnamese jurisdiction over the nation, which was formally made a protectorate, adding to his prestige.

[24] In the early 1820s, Duyet dispatched a delegation to seek out British officials in an attempt to buy arms, but the party got lost in storms and were arrested after washing up in Burma.

[17] During the final four years of Gia Long's reign, Duyệt ascended to the highest rank in the court, and he and Pham Dang Hung, another southerner, were the only people present as the emperor died.

[18] At the beginning of his second period as viceroy, Duyệt suppressed a revolt of the local Khmer people and enlisted ten thousand new taxpayers, thereby generating a large new revenue source for the court.

Although Gia Long had enlisted European support to claim the throne and allowed missionaries to function in Vietnam in gratitude to Pigneau,[30] he ran a classical Confucian administration.

He also expressed dismay at the Catholic condemnation of the traditional ancestral worship, a basic tenet of Vietnamese culture; Crown Prince Cảnh had been converted by Pigneau and subsequently refused to bow down to his ancestors, instead desecrating a shrine with feces.

[32] Gia Long chose him for his strong character and his deeply conservative aversion to Westerners, whereas Cảnh's lineage had converted to Catholicism and had shunned Confucian traditions such as ancestor worship.

[35] Historian Mark McLeod said that "As the head of a region enjoying substantial autonomy, Lê Văn Duyệt had good reason to prefer that the empire be ruled after Gia-long's death by an immature or malleable monarch.

"[35] According to McLeod, as Duyệt was not from a scholar-gentry background and lacked a classical Confucian education, he did not place a great emphasis on tradition and was more concerned with military needs, and that as a result, he would be more interested in maintaining strong relations with Europeans so that he could acquire weapons from them, rather than worrying about the social implications of Westernization.

These included many former rebels who were spared the death penalty after being defeated by Duyệt in northern and central Vietnam during his pacification campaigns in the late 1810s, and had sworn loyalty towards the general personally.

[42] These men were sent south with their wives and children to remove them from potentially rebellious areas and to punish them, but another objective was to start military colonies to help develop southern Vietnam, which had only recently been acquired by ethnic Vietnamese.

[43] Duyệt and Gia Long had employed surrendered Tây Sơn officers in positions of authority, and this policy had continued due a shortage of manpower until Minh Mạng came to power.

[44] For Minh Mạng, the placement of former convicts and rebels in positions of power was contrary to the Confucian system of order and debauched the prestige of the state, whereas Duyet was only concerned with practicality.

[45] During the 1820s, Duyệt's continued cultivated of relations with the immigrant Chinese community that had settled in southern Vietnam in large numbers brought him into conflict with Minh Mạng.

The Japanese historian Shimao concluded that Duyệt and his entourage were given financial rewards and gifts from the Chinese merchants in return for favourable treatment by government officials.

It was thought that Chinese merchants, whom Duyệt patronised, were illegally exporting rice at higher prices, and then bringing back opium during return journeys along with incoming immigrants.

[48] For his part, the general disagreed with the prevailing view held by the emperor, and said that people of both races were engaging in illegal trading, as well as blaming the incoming immigrants' personal addictions rather than the Chinese merchants for bringing in opium.

[47] The historian Nola Cooke said that Duyet's viewpoint was more plausible and speculated that the emperor's stance was borne more out of a fear of the consequences of a disproportionate Chinese influence on the country than the reality of illegal trading.

Because of their involvement in the illegal exportation of rice and importation of opium, Minh Mạng tried to ban the Chinese from engaging in sea trade in 1827,[47] but this was easily circumvented by the merchants, who exploited their contacts with Duyệt and used fraudulent registrations, often under the name of Vietnamese wives.

One of the objectives was that they would oversee the imperial examination process and education system, which would allow them to determine who would serve in the government as mandarins and therefore fill the southern ranks with men acceptable to the court.

[54] In 1823, one of Duyệt's closest subordinates Tran Nhat Vinh, was indicted by one of Minh Mạng's officials from Huế, who charged him with trading rice on the black market and operating a brothel.

The following year, Duyệt executed convicted criminals without informing the capital, leading the emperor to criticise him again, saying that "the ultimate authority to decide questions of life and death belongs to the court.

[55] In 1831, just before Duyet's death, Minh Mạng began to dismantle his military infrastructure and sending his component units to other parts of Vietnam, and sent a loyalist General Nguyen Van Khue to Gia Định, allowing him to dilute the viceroy's power.

[62] This was attributed to Gia Long's dependence on military officers during the war years, which required him to be blunt and assertive, whereas Minh Mạng grew up dealing with court scholars after the establishment of the Nguyễn dynasty, and was regarded as a quiet and studious monarch.

[67] This was allowed to continue despite a legend in southern Vietnam that Duyệt had appeared in the dreams of Nguyen Trung Truc, a fisherman who famously led a peasant army against French colonization, and advised him on how to fight foreigners.

Choi described Duyệt's popularity as follows: "No matter whether they are indigenous Vietnamese or Chinese settlers, Buddhists or Christians, residents of Saigon have long paid enthusiastic tribute to one favorite southern, local hero—Lê Văn Duyệt—whose gorgeous shrine is located on Dinh Tien Hoang Street in Binh Thanh District.