One of Gia Long’s final decisions would have a long-term effect on Khmer–Viet relations. In 1819, Gia Long decided to dig what became the Vinh Te and Vinh An Canals. Gia Long’s stated intention was to benefit Cambodia by creating a more convenient water route from the Khmer capital to the sea and to benefit Vietnam by completing an inland water route connecting all administrative centers in the Mekong plain. The Vinh Te Canal would link Ha Tien, on the Gulf of Siam, with Chau Doc, on the southern branch of the Mekong River. The Vinh An Canal extended the Vinh Te Canal to the northern branch of the Mekong River with access to Vinh Long, My Tho, Saigon, and Bien Hoa. Plans for the canals were prepared in consultation with Ang Chan, and workers from both countries were mobilized for the task, reportedly five thousand Khmers and five thousand Viet- namese, along with five hundred Vietnamese soldiers. The Khmer and Vietnamese workers were organized and supervised by officials of their own countries. Gia Long ordered that every worker, both Khmer and Vietnamese, was to receive a monthly allotment of rice and a cash salary. He acknowledged that it would be hard labor but that the benefit for future generations would be great. Gia Long completed arrangements for work on the canals in late 1819, shortly before his death, and construction began after the new year holiday.
By late spring 1820, with the work about one-third completed, reports that the workers were suffering from the effects of hard labor prompted Minh Mang, the new king at Hue, to issue an appeal to the Khmer king and his officials encour- aging them to persevere in the common task. At the same time he gave orders to distribute medicine to sick workers and to issue money and cloth to the families of workers who died on the job. He also ordered that the scale of the remaining work be temporarily reduced to allow passage for small boats only. That summer, when the monsoon rains arrived, an epidemic spread among the workers and into the neighboring population. The Hue court sent instructions for prayers to be made, medicine to be distributed, and burial costs to be paid at public expense. According to a Khmer source, bad working conditions were exacerbated for the Khmer by the arrogant and unsympathetic attitude of Vietnamese officials, producing dissention among the Khmer officials in charge of the workforce; this led many Khmer laborers to abandon the project and to return to their villages. In fact, soon after the coming of the summer rains, the project was suspended and all workers were sent back to their homes.
The digging of these canals had commenced as the Hue court was distracted by the death of one king and the accession of another. Local Vietnamese officials nevertheless already had prior experience mobilizing thousands of workers for canal work and organizing logistics for food, housing, and equipment. For example, in early 1819, around twenty thousand people had been mobilized for canal work in the Saigon and My Tho areas. Cambodian officials had no comparable prior experience and expected the Vietnamese to take responsibility for problems. The canals were eventually completed during the springtime dry seasons of 1823 and 1824 with a workforce of around fifty thousand men in 1823 and twenty-five thousand in 1824, two-thirds of which in both years was comprised of Vietnamese militiamen with Khmer laborers constituting the rest. Today, the Vinh Te Canal marks the border between Cambodia and Vietnam.
In autumn of 1820, a Khmer Buddhist monk named Ke, in the region of Ba Phnom east of the Mekong River, initiated a rebellion against King Ang Chan. Ba Phnom is in the center of a triangle formed by Phnom Penh, Chau Doc, and Tay Ninh, being about seventy kilometers from each of these places. Cambodian historians have commonly assumed that this uprising was an anti-Vietnamese revolt provoked by conditions at the canal worksite. Ba Phnom is rather far away and across the Mekong River from the worksite. Khmer workers were mostly mobilized from the modern provinces of Kampot and Takeo, directly adjacent to the worksite south of the Mekong River, judging from French reports of mem- ories among peasants in those areas later in the century. Consequently, Khmer workers returning to their villages were unlikely to have gone anywhere near Ba Phnom. With Ang Chan’s attention focused on the worksite, however, it was an opportune time for Ke to initiate his uprising.
Ke appears to have been motivated by Ang Chan’s reliance upon Chams at least as much as he was by his hatred of Vietnamese. Ke was unhappy about Ang Chan showing favor to a Muslim Cham leader named Tuan Pha, who had become one of Ang Chan’s trusted subordinates. Muslim Cham communities had been established in areas near Ba Phnom for several generations and friction between them and the Buddhist Khmers was in the background of Ke’s uprising. Instead of leading his followers across the Mekong River to the canal worksite where he could presumably have mobilized disaffected Khmer workers, Ke advanced in the opposite direction and ravaged the region of Tay Ninh, far from the canal, which was inhabited by Chams and Vietnamese.
The Vietnamese garrison at Gia Dinh was unsuccessful against Ke, but Le Van Duyet soon arrived with soldiers from the north and pushed the rebel army back into Cambodia. Ke then led his followers to attack Phnom Penh. Ang Chan sent Tuan Pha against the rebels, but several Khmer generals defected to Ke and Tuan Pha was repulsed. Within a matter of weeks, Le Van Duyet led a Vietnamese army up the Mekong and joined with Ang Chan’s army, comprised mainly of Chams and Chinese, to utterly defeat the uprising, killing Ke in battle. By the end of the year, Le Van Duyet took his army back to Vietnam, leaving a 700-man garrison at Phnom Penh. Ang Chan had become a docile Vietnamese vassal. So long as Le Van Duyet lived, the Siamese made no attempt to challenge this state of affairs. After the Cambodian campaign of 1820, Le Van Duyet served as the viceroy at Saigon until his death, twelve years later.
During Gia Long’s reign, Le Van Duyet had specialized in crises requiring military responses. Aside from Cambodia, two other areas had occupied much of his attention. Depredations of the “stone wall” people in Quang Ngai, which had absorbed Nguyen Cu Trinh’s attention in the 1750s, became chronic after the wars. Le Van Duyet carried out major operations in Quang Ngai Province four times between 1803 and 1815. He finally arranged a defensive system of walls and garrisons facing the mountains that extended from Quang Nam Province through Quang Ngai to Binh Dinh Province.
Le Van Duyet spent several months during 1819 in Nghe An and Thanh Hoa, where reports of banditry and insubordination had accumulated. He reported that misgovernment by incompetent, corrupt, and oppressive local officials had led to peasants fleeing from their villages and soldiers rising in mutiny. After consulting with Gia Long, he appointed new officials, forgave unpaid taxes, reduced corvée obligations, and thereby restored order. Some places required military action against bandits and small armies of disaffected fugitives. As much as possible, Le Van Duyet made use of local military leadership. He was also willing to incorporate surrendered rebels into his military units. His method of pacification was based on winning the cooperation of local people and appears to have been mostly successful. After this assignment, Le Van Duyet oversaw the accession of Gia Long’s successor at Hue before traveling south to deal with the Cambodian uprising.