“Nam Tien” and Indochina’s First Genocides against Cham and Khmer populations
“It is thought that the majority of Chams were killed, driven off, or assimilated by the Vietnamese. Chams still exist today as an ethnic minority in Vietnam — though its number is relatively small (about 40,000) in comparison to the 30,000 Cham families in the eleventh century.”
“To be sure, however, the Nguyen’s colonial[ists] did displace the local populations of the Chams and the Khmers, whose “displacement but not replacement” is still today not assured.”
“Like the Chams, the Khmers were also “discredited” of their role in developing the commercial areas near Saigon. Their contribution to the Vietnamese vocabulary and phrases is often overlooked. This is also true regarding their religious practices, which the Vietnamese have adopted, including elements of Theravada Buddhism. Other cultural borrowing from the Khmers includes agricultural implements and foods, medicines, and different areas of arts.”
In Vietnamese history, a theme that transcends across time and space is the advance or the march to the south (“nam tien”). The southern advancement, as noted by Michael Cotter, is unique in that “it transcends the different periods of Vietnamese history – pre-Chinese, Chinese, independent, colonial, and contemporary” in which each has “its own theme.” 
As discussed in earlier blogs, Chinese colonial diasporas had both indirect and direct effects on the southern advancement.
For Vietnamese, they have been “victims” of Chinese colonial diasporas — being physically, psychologically, culturally, and intellectually displaced. However, as noted by other scholars, the “Vietnamese will to [in]dependence was too strong,” there must have been “a special Vietnamese collective identity of some sort,”  and the “harmony between the Vietnamese . . . and their environmental conditions has proved to be so deep that no race has been able to resist their advance.” 
Simply, Vietnamese have always maintained their relationships with the collective memory and myth about their birth place and never more passionately than when displacement and disunity was imposed by foreign rule.
However, Vietnamese collective will to resist had to be modified because of Chinese military power in which resistance had to include strategic form of borrowing and localizing ideas of foreign powers in order to make and strengthen local cultural statements about its “Vietnamese cultural core.”
Cultural borrowing came from both north and south. And until late in the 14th century, Buddhism had acted as a common ground between Vietnam and southern states of the Cham and Khmer, during times of both peace and war; for instance, Vietnamese prince who married Cham princess and the Vietnamese Buddhist monk who practiced Indian asceticism. 
Vietnamese, on the one hand, were successful in localizing external influences in which what were borrowed were considered essential and integral to the culture at that particular time. But such situation sometimes was inevitably imperfect and had led to tension and stress within the society on the other. 
This was the case, when after repelling the Ming invasion (1407-1427), the Le emperors began to adapt the Ming Chinese model and began to transform ideologically, bureaucratically, and militarily.
This transformation enabled the Vietnamese state (Dai Viet) under the Le dynasty (1428-1524) to stabilize its southern and western frontiers. But in doing so, the conviction in the essential unity of their territory and people and cultural relativity began to take dual form or multiple forms (or even change character).
The External Expansion of Dai Viet
The transformation of Dai Viet was, in part, the result of its population becoming a specialist in wet-rice cultivation, which fostered “the trade, population growth, and resource concentration that promote state power and societal expansion.” 
Importantly, the state began to adapt the Ming Chinese model.
For example, it took on the Chinese ideals of bringing ‘civilization’ to the ‘uncivilized,’ which were applied to its relations with Champa and the Khmers. It also adapted Chinese meritocratic civil service examinations as the method of recruiting educated talent to service the government.  Moreover, Dai Viet had acquired gunpowder technology from China, although Vietnamese also had contributed to Chinese gunpowder technology by locally producing better techniques such as the wooden wad and possibly a new ignition, which was then exported to China.  Arming itself with new gunpowder technology, Dai Viet’s large and well-organized military force was able to achieve its military ends more easily than before. 
Indeed, under the Le dynasty, the Vietnamese state began to transcend its displacement and, according to one opinion, gradually developed into “a bigger hegemonist,” conceiving themselves as superior to all other peoples in Southeast Asia. 
But probably more accurate is that the transformation of Dai Viet changed the balance of power in mainland Southeast Asia. Yet, that balance was tenuous and was hampered by the eventual rise of two separate entities with two different representations of “what was a good Vietnamese.”
Notwithstanding, as a result of the above transformation, Dai Viet, on the one hand, were able for the first time, since independence, to stabilize its southern and western frontiers. But Dai Viet also took advantage of its new capabilities to end its conflicts with Champa over areas (that of Quang Binh, Quang Tri, and Thua Thien) where the two mingled since the fifth century.
Between 1361 and 1390, Champa, under Che Bong Nga’s rule, conducted an interrupted series of victories against Vietnam, including the sacking of Vietnam’s capital of Thang Long several times and were able to retrieve Champa’s old northern provinces that it lost earlier in 1301 through a marriage alliance that did not endure. But after Che Bong Nga’s assassination in 1390, Champa had to hand back the provinces to Vietnam, yet these areas were still contested until the fifteenth century. However, in 1471, the Dai Viet’s military force appeared to have overwhelmed the Chams. One thousand Dai Viet warships and 70,000 troops captured Champa’s capital of Vijaya. According to Vietnamese source, more than 30,000 Chams were captured and over 40,000 were killed. In part, the fall of Champa in 1471 was due to the fact that it did not have access to firearms.  Thus, the year 1471 marked the rise of Dai Viet.
Vietnamese had by then conquered the northern part of Cham country, as far as the southern border of today’s Binh Dinh province. However, Cham kings continued to rule from this region, although less autonomous then earlier Cham kings. In addition, however, there were southern Champ polities, including a fourth Cham region (Kauthara) located near present day Nha Trang, which had been a part of Cham country since the beginning of Cham history.
On Vietnam’s western borders, Tai peoples were actively crossing Vietnam’s western borders, causing a series of conflicts between the two. But by the late 1470s, Dai Viet was able to claim Tai hill territories, bringing the Tai ethnic groups in modern Vietnam.  Taking advantage of its military technology, Dai Viet also pursued aggressive actions against Thai and Laos principalities. Its armies marched as far as the Irawaddy River in modern Burma.  As a result, by the early 1480s, kingdoms of northwestern mainland Southeast Asia, such as the Laotian kingdom of Lan Ch’ang and Thai principality of Ai Lao sent tributes to the Vietnamese capital.
In sum, the purpose and scope of Dai Viet’s external expansion was initially to stabilize its southern and western frontiers, of which had been militarily contested throughout the centuries without a clear winner, at least until 1471. Its external expansion was dynastic in nature, which was clearly reflected by the reign of Le Thang Tong (1460-1497) who sought to stabilize his state by securing its borders to prevent any repeat of foreign invasions, such as the Ming invasion of 1407-1427. The degree of success in stabilizing its borders, as well as going beyond its borders, was, in large part, due to the unilateral-monopolistic timing, as put forward by Frank Darling.  That is, Dai Viet’s external expansion occurred because of a “power vacuum” in which Dai Viet with the new gunpowder technology and under a more bureaucratic state were able to exert power in the region, limited by the available resources and the stability of the Le court.
Vietnam, however, did not develop a permanent colonial phase or colonial diaspora until the beginning of the sixteenth century. Even though Vietnam was active in acquisitioning Cham lands, it occurred at long intervals. In occupying Cham lands, the Le emperors would appoint frontier military governors with the rank of viceroy (kinh-luoc), but would also retained Cham officials in the administration in some regions. The purpose and scope of Vietnamese military and penal colonies were to consolidate their gains, to provide support for expeditions, and to relieve population pressures. 
During this period, Vietnamese rulers did not pay much attention to the specific matter of expansion into Champa, until the arrival of the Nguyen lords who eventually sought a southern autonomous state, separate from the northern state under the Trinh lords.
The Nguyen’s Colonial Diaspora
Vietnamese southern expansion or colonial diaspora under the Nguyen family can be described as a frontier movement, originating because of political and military unrest and conflicts at home; and expanding through military conquests, treaties, and “most difficult to document, colonization by transfrontiersmen.” 
In 1524, when the Le emperors were usurped by the Mac family, the Trinh family and Nguyen family both professed their loyalty to and attempted to restore the Le emperors. However, after the restoration of Le in 1592, the Trinh family gradually acquired all the important posts at the Le court so that the Le emperors were reduced to being “nominal” rulers.  Meanwhile, the Nguyen family saw the Trinh as usurpers and decided to officially break with the Trinh in 1600 and return to Thuan Hoa (modern Hue), where years earlier they were emplaced by the Trinh to establish control over the southernmost frontiers. Between 1627 and 1672, the Nguyen lords were able to defend Trinh’s expeditions, as well as defending Cham’s reacquisition of its former territories. By 1672, Trinh lords, whose militarily failures to defeat the Nguyen left them weakened, agreed to a division of the two states at the boundary of the Linh River. This resulted in a relatively stable coexistence of “two Dai Viets” for a little more than one hundred years.
The Nguyen, despite having a smaller population with a smaller number of trained officials, accordingly adjusted their organizational structure and localized themselves to their new geographical terrains and frontier influences, including redeveloping trading centers, absorbing local populations, and interacting with foreign merchants.
For example, in the former Cham territories, one of the key characteristics of the Nguyen administration was the use of Chams and of lower-class Vietnamese. It also redeveloped the commercially oriented society center in Hoi An, which had been pioneered by the local Cham population who still constituted a key component in the labor and basic patterns of the region’s trading center after the Vietnamese takeover.  Unlike the traditional northern economy, the Nguyen’s economy had a “fundamental basis in foreign trade.”  This attracted Vietnamese immigrants, as well as Chinese refugees who fled from the Manchu dynasty, arriving at various times in present day areas of Hue after 1636, further transforming the Hoi An region “into its now recognizably Vietnamese form.”  Moreover, from its contacts with foreign merchants, the Nguyen state was able to arm itself with modern weapons provided by Portuguese merchants, which assisted them to defend the Trinh expeditions as well as to continue the expansion of its control farther south.
As noted by recent works in Vietnamese historiography, in the Nguyen, we see a new version of being Vietnamese. Although these works tend to describe the Nguyen as breaking or escaping from the past and from the ancestors in order to create ways of being Vietnamese,  it is probably more accurate to say that the Nguyen was not rigid in conforming with the traditional culture in the north, which led to a more open, multiethnic society with emphasis on foreign trade.
“. . . since the early 1620s Khmers were gradually displaced and were pushed out of their villages into Cambodia or into marginal lands near the sea; and by 1780, the Vietnamese controlled most of the southern territories that comprise present Vietnam. During the 18th century, military colonies were used to expand in this region, which settled disputes between Khmers and encroaching Vietnamese, although in the favor of Vietnamese settlers.”
This was true for both the central areas and the Mekong Delta areas. In the latter, Vietnamese had moved into southern plains by the early 1620s, due the political and military vacuum left by the declining Khmer kings. By this time, the Khmer court based in Phnom Penh was faction ridden and was subservient to Siamese (Tai) influence. This allowed the Nguyen to exert its influence in the Khmer court, including the marriage of a Vietnamese princess to a Khmer king in 1620. Three years later, the Khmer king granted permission for Vietnamese immigrants and traders to move into the areas, culminating in 1689 the establishment of a viceroyalty over the provinces around Saigon (Cotter254). 
Compared to the central areas, the Nguyen saw the Mekong Delta as more extensive and fertile for growing rice. It also used this area to utilize captured Trinh soldiers and lower class immigrants from the north to settle and develop this area. Chinese immigrants also had important role in redeveloping this region’s trading center. As a result, this region was ethnically pluralistic. From one perspective, these individuals and groups found southern Vietnam as a land of promise, where they could make a fresh start.  For instance, captured soldiers were expected to clear the land in which they were given farm implements and food to eat. So in several years “they could produce enough for their own needs,” and after twenty years after “their children can be soldiers of the country.” 
To be sure, however, the Nguyen’s colonial[ists] did displace the local populations of the Chams and the Khmers, whose “displacement but not replacement” is still today not assured.
A common perception is that the institutional weakness of Cham society, “a weakly institutionalized state system that depended upon personal alliance networks to integrate a fragmented population,” had sealed its fate.  Yet, the Chams were never easily conquered. In fact, it may be the same decentralized system that allowed the Chams for centuries to contest and stir rebellion against the Vietnamese. Despite the Nguyen’s presence in the Cham territories since the 1550s, it was until 1611 that Cham territory of Kauthara (modern Nha Trang) disintegrated and not until 1771 that Panduranga-Champa (modern Phan Rang) fell. However, over the centuries Cham society could not withstand the Vietnamese advancement, sometimes in “massive convulsions or in fits and starts.” 
It is thought that the majority of Chams were killed, driven off, or assimilated by the Vietnamese.  Chams still exist today as an ethnic minority in Vietnam — though its number is relatively small (about 40,000) in comparison to the 30,000 Cham families in the eleventh century. To some degree, because the Nguyen’s purpose and scope of its colonial diaspora were of political and economic domination “with less concern about Cham social and religious life,” Chams were able to retain some of their culture, including their language, religious beliefs, matrilineal kinship patterns, and the practice of non-intensive rice growing.  And often overlooked or discredited is the contribution of Chams in the Hoi An region as international trade center. It is very likely that “Vietnamese immigrants encountered the well-established patterns of behavior of the peoples who preceded them and very likely continued to live alongside them.”  For instance, Vietnamese had been shaped by the Cham maritime logic in rebuilding Hoi An, learned to grow rice in terraced land, adopted local Cham deities such as Po Nagar, took up a form of Siva worship, lived in Malayic-style stilt houses, traveled in Cham-style boats, tilled with Cham plows, buried their dead in Cham-style graves, and practiced piracy and barter in slaves. 
Similarly, since the early 1620s Khmers were gradually displaced and were pushed out of their villages into Cambodia or into marginal lands near the sea;  and by 1780, the Vietnamese controlled most of the southern territories that comprise present Vietnam. During the 18th century, military colonies were used to expand in this region, which settled disputes between Khmers and encroaching Vietnamese, although in the favor of Vietnamese settlers.  In the 1978 border war with Cambodia, the new socialist government of Vietnam used the Khmers as an advance column in their invasion into Cambodia. Like the Chams, the Khmers were also “discredited” of their role in developing the commercial areas near Saigon. Their contribution to the Vietnamese vocabulary and phrases is often overlooked. This is also true regarding their religious practices, which the Vietnamese have adopted, including elements of Theravada Buddhism. Other cultural borrowing from the Khmers includes agricultural implements and foods, medicines, and different areas of arts.
Source: University of Houston