As described in earlier chapters, the Vietnamese had experienced centuries of contact, both hostile and peaceful, with the Chams and related upland peoples who spoke languages affiliated with the Malay peoples of the coasts and islands of Southeast Asia. By the seventeenth century, there had been much mingling of Chams and Viets along the southern coast. Although many Chams had fled further south, into the mountains, or into the sea with each advance of Vietnamese conquest, many others had chosen to remain, took Vietnamese names, adopted Vietnamese habits, and over time became Vietnamese. Cham soldiers served in Vietnamese armies and were led by Cham officers. The army sent by Nguyen Hoang to conquer Phu Yen in 1611 had been commanded by a Cham general. For forty years after 1611, the Cham population of Phu Yen continued to elicit efforts by Cham kings to retake this rich province. Phu Yen lay in the coastal plain of the Da Rang River, which drained a large part of the adjacent uplands and was the last region suitable for large-scale agriculture before passing through relatively arid, semi-desert lands on the way to the Mekong River plain. Con- fined to a dry coastal strip, Cham leaders struggled to redefine their authority. In 1613, the Cham king had withdrawn his capital from Phan Rang to Phan Ri, which was futher south, possibly seeking greater distance from the Vietnamese threat, but just as likely in response to tension between Hindu and Muslim Chams. The Muslims appear to have been dominant at modern Nha Trang, the last Cham seaport. In 1622, a Hindu king was killed and replaced by a Muslim king, who chased off visiting Jesuits, attacked Dutch ships, and provoked bitter fighting between Cham Hindus and Cham Muslims. This strife attracted the participation of neighboring upland peoples in modern Lam Dong Province. The Churu, Ede, and Jarai were ethno-linguistically related to the Chams and for centuries had been part of the larger political, economic, and cultural world of the Chams. They were neither Hindu nor Muslim. Their societies were matrilineal and matrilocal. Women initiated marriage, men joined the families of their wives, and children inherited property through mothers. These peoples intermarried among themselves and also with the Chams. As the coastal Cham population declined and was increasingly limited to the sandy lands that faced southeastward to the sea, the role of the uplanders in Cham political life increased. In 1627, a Churu chieftain known as Po Ramo subdued both Hindu and Muslim factions and forced peace between the two Cham communities. He was originally from Don Duong district near the modern city of Dalat. He ruled from the Phan Rang basin and built dams and canals to nurture agriculture in that region. He still had the seaport at Nha Trang and for a quarter-century presided over a small surge of prosperity among the Chams. His three principal wives were daughters of a previous king, of an Ede chieftain, and of Nguyen Phuc Nguyen. Although for two decades his leadership went far toward stabilizing the Cham–Viet border at Ca Pass, he could not stay clear of continuing tensions between the Cham and Vietnamese communities in Phu Yen. In 1651, Po Ramo was wounded in Phu Yen during an outbreak of hostilities between Chams and Viets. He died of his wounds. Po Nraup, one of his half- brothers, a son of his Churu mother and a Cham father, took authority and went on the offensive, attacking Phu Yen and driving Vietnamese soldiers and officials out of that province. Nguyen Phuc Tan sent an army of three thousand men under the command of a Cham general known as Hung Loc. Hung Loc not only retook Phu Yen, but he also continued his advance to Nha Trang. He captured Po Nraup and forced him to cede all territories north of the Phan Rang River. Po Nraup died shortly after this, and in the turmoil of Vietnamese conquest a son and a grandson of Po Ramo were successively but briefly appointed as vassal kings by the Vietnamese until a measure of calm was restored under a Cham lord named Po Sot, who, from 1659 to 1692, governed at Phan Ri. The Chams, deprived of a seaport and of good agricultural land, went through another major demographic adjustment as many Muslims took the upland road from Nha Trang across the Central Highlands to the Mekong and beyond to Siam, where they settled at Ayutthia. The new border placed the modern province of Khanh Hoa, where Nha Trang is located, under Vietnamese administration. Po Sot presided over the last sem- blance of a Cham kingdom before Cham kings were reduced to being adminis- trators of a minority people in a Vietnamese kingdom. The seventeenth century also saw the first Vietnamese contact with the Khmers of Cambodia and with the Siamese, whose rising influence over Cambodia elicited Vietnamese interest in Khmer royal politics. At that time, Cambodia included the entire lower plain of the Mekong River. The western provinces of Cambodia were increasingly subject to Siamese power. At the same time, the Vietnamese, allied with immigrant Chinese, established a sphere of action in the eastern Cambodian provinces. Around two centuries earlier, Khmer kings had abandoned Angkor, which was located to govern an agricultural empire that included large parts of modern Thailand. They shifted to sites on or near the Mekong River with access to the sea and a new source of wealth that was based on international trade. In the late fifteenth century, Siam achieved a new level of regional ascendancy under the leadership of Naresuan (reigned 1590–1605). When they could no longer resist the Siamese, Khmer kings solicited military assistance from the communities of foreigners who had gathered in their kingdom attracted by trade: Chinese, Japanese, Malays, Chams, Portuguese, and Spanish, but to no avail. In the first decade of the seventeenth century, Cambodia was reduced to the status of a Siamese vassal. However, in 1618, Chei Chéttha II became king of Cambodia and, with Siam under threat from Burma, he repudiated Siamese vassalage in a way that elicited the beginning of Vietnamese involvement in Cambodian affairs. Chei Chéttha II turned to Nguyen Phuc Nguyen for assistance in resisting the Siamese. It seemed to be a good idea because there was no common border with the Vietnamese and the antagonism between the Trinh and the Nguyen promised to keep them busy with each other. Nguyen Phuc Nguyen married his second daughter Ngoc Van to Chei Chéttha II. With her went an entourage of around 1,000 Vietnamese, including soldiers to serve as bodyguards and a Vietnamese official to serve as resident ambassador. In 1622, the Vietnamese participated in a naval battle that defeated a Siamese invasion. A community of Vietnamese began to form at the Khmer capital. In 1623, Nguyen Phuc Nguyen asked Chei Chéttha II for the authority to collect taxes at Prei Nokor and Kampong Krabei. These were adjacent settle- ments that were the economic and administrative centers of the easternmost Khmer province, in the basin of the Daung Nay (Vietnamese Dong Nai) River on the Cham frontier. Khmer histories affirm that Chei Chéttha II agreed to this as a temporary arrangement of five years, supposedly to give his ally some consideration for the assistance against Siam in the previous year. Khmer historians may have interpolated the idea of a five-year term for this arrangement to support later requests by Khmer kings that the Vietnamese return the privil- eges they had been granted, but this does not take into account that a population of Chinese and Vietnamese traders and adventurers was already accumulating in the basin of the Dong Nai River. Prei Nokor was a Chinese commercial center on the site of modern Cholon (“big market”), the Chinese district of modern Saigon. A Chinese population of merchants was already established there. It was situated to take advantage of waterways connecting the eastern part of the Mekong plain with access to the sea via the Sai Gon and Dong Nai Rivers. Kampong Krabei (Vietnamese Ben Nghe) was on the Sai Gon River, on the site of modern Saigon, and was primarily an administrative center. A Vietnamese garrison was established there, and officials were assigned to collect revenue, to report events in the region, and to keep some measure of order among the Chinese and Vietnamese population, which included banished criminals, fugitives, and vagabonds as well as merchants and agricul- turalists. The Vietnamese called the Kampong Krabei garrison by the name Gia Dinh. When Chei Chéttha II died in 1627, his eldest son reigned for five years as Srei Thoamareachea I. However, Chei Chéttha II’s younger full brother Barom Reachea exercised great authority as the “second king” (opphayoreach). Vietnamese envoys arrived bearing gifts and requested that Ngoc Van, Chei Chéttha II’s Vietnamese widow, be elevated to the rank of “queen mother,” the highest position for a woman at court. She had given birth to a daughter but had no sons. In consideration of the importance that the Khmer court gave to the Vietnamese alliance, this request was granted. With the envoys came 500 Viet- namese soldiers to reinforce her bodyguard. In 1632, Srei Thoamareachea I provoked a war with his uncle Barom Reachea by indulging in an affair with Barom Reachea’s wife. Srei Thoamareachea I had encouraged a large influx of Chinese residents during his years as king and they supplied him with troops in the struggle with his uncle. For his part, Barom Reachea’s forces included a contingent of Portuguese. Srei Thoamareachea I was defeated, killed, and replaced by a younger brother, Ang Tong Reachea. How- ever, Barom Reachea was the actual ruler. Shortly after, as Nguyen Phuc Nguyen was preoccupied with his northern border and with his approaching death, Barom Reachea requested that the Vietnamese evacuate Prei Nokor and Kam- pong Krabei. This request was withdrawn after the intercession of the Vietnam- ese “queen mother,” Ngoc Van. In the late 1630s, the Dutch established a trading station in Cambodia, introducing a new source of tension into the kingdom in the form of Dutch–Portuguese hostility that was prone to erupt in violence. When Ang Tong Reachea died in 1640, Barom Reachea placed his own son on the throne as Botum Reachea I. A son of Chei Chéttha II refused to accept this, however, and in 1642, with the support of Ngoc Van, he killed his uncle Barom Reachea and his cousin Botum Reachea I, along with many members of their family and officials who had supported them; he then took the throne as Reameathipadei I. He married a Muslim, identified in some texts as Malay and in others as Cham, and converted to Islam (taking the title Sultan Ibrahim), thereby gaining the support of the Malay and Cham communities and their military forces. He took the side of the Portuguese against the Dutch, which led to a brief war with the Dutch that ended with their expulsion. Vietnamese merchants became more active in Cambodia at this time, particu- larly in buying rice needed to supply the heavily militarized population among the walls on their northern frontier. Ngoc Van preserved her high position as “queen mother” with her own palace and entourage. She continued to deflect tentative Khmer efforts to regain Prei Nokor and Kampong Krabei. Two of Barom Reachea’s sons, Ang So and Ang Tan, who had escaped the homicidal inauguration of Reameathipadei I’s reign, found safety in her entourage, as did her grandson, Srei Chei Chét, the son of her daughter and of Botum Reachea I. These princes were determined to avenge the deaths of their fathers. In 1658, as King Narai of Siam made a show of preparing to invade from the west, Ang So led a rebellion against Reameathipadei I. Ang So easily raised support from the Buddhist leaders who were alienated from the Muslim king, but Reameathipadei I raised a large army that included Malays, Chams, some 150–200 men from the Vietnamese garrison, and the ships of Europeans that happened to be in Cambodia at the time, including the Dutch (who meanwhile had made peace with Reameathipadei I and had regained a trading station in the country), the English and, briefly, the Spanish and the Danes. Having endeavored during previous years to keep the peace between Reameathipadei I and the princes whose fathers he had killed, the Vietnamese queen mother Ngoc Van was caught in the middle. Nevertheless, when the rebellion began to fail and Ang So appealed to her, she sent a request to Nguyen Phuc Tan for help. At that time, Nguyen Phuc Tan was engaged in a prolonged invasion of the north that had begun three years before. He was determined that the Gia Dinh garrison not be disturbed, for it was an important source of wealth and supplies. Other than that, he was not concerned about who would rule Cambodia, but he saw an opportunity to launch an expedition for plunder to supply his armies in the north and to degrade the potential of Khmer kings to oppose his policies in the future. In late 1658, he sent a fleet with around 3,000 well-trained and disciplined men down the coast and up the Mekong. Its sudden appearance in the heart of the Khmer kingdom gave Reameathipadei I little time to prepare for the river battle that ensued. Reameathipadei I was captured, and the Vietnamese systematically looted the capital of Oudong, loading around one hundred boats with plunder, including gold, silver, various weapons, and 1,600 pieces of artillery. They also obtained eight hundred elephants and even more horses. Among the assets the Vietnamese found in Cambodia was a Portuguese cannon maker named Jean de la Croix. When they departed Cambodia in spring of 1659, the Vietnamese took this man with them and set him to work in their gun foundries. When he understood that the Vietnamese had come on a looting expedition, Ang So resisted them and, when the Vietnamese had left, he proclaimed himself king as Barom Reachea VIII. Nguyen Phuc Tan sent Reameathipadei I back to Cambodia as his vassal, but he died along the way. An army of Cham and Malay Muslims rose up against Barom Reachea VIII, who was a devout Buddhist, but were defeated and took refuge with King Narai of Siam. Barom Reachea VIII gave particular preference to the Chinese community in Cambodia. In 1667, a large group of Chinese, reportedly over 3,000, arrived from Taiwan. In a surprise attack that had the approval of Barom Reachea VIII, the Chinese set upon the one to two thousand Vietnamese who resided near the capital, killing most of them, capturing some, and sending the survivors fleeing north. The Chinese then set upon the Dutch, seizing their property, killing many and expelling the rest. Thus, the Chinese removed their two largest competitors for control of the local economy. Barom Reachea VIII proclaimed an end to relations with the Vietnam- ese and prohibited them from entering his kingdom. This had no effect upon the Vietnamese garrison at Gia Dinh, which remained as before. Barom Reachea VIII was killed in 1672 by his nephew, Srei Chei Chét, who appears to have had no greater motive than an urgent desire to be king. The regicide’s uncle, Ang Tan, who was the “second king,” feared for his own life and fled to the court of Nguyen Phuc Tan, leaving behind his wife, a prominent princess, as well as his nephew and adopted son, Ang Nan, the son of a deceased younger brother, who reportedly had been Barom Reachea VIII’s designated heir. When Srei Chei Chét attempted to make Ang Tan’s wife his queen, she had him killed and, following her advice, the royal court sent for the eldest son of Barom Reachea VIII, who had meanwhile become a forest monk, and enthroned him as Kèv Fa II. Rivalry between Kèv Fa II and Ang Nan quickly spun out of control. Kèv Fa II made a show of calling in the Siamese to pacify Ang Nan. In 1674, Ang Nan departed to seek assistance from the Vietnamese. On the way, he met Ang Tan accompanied by the second Vietnamese expedition to Cambodia. Unlike the first expedition of 1658, which had essentially been for plunder, this expedition was prepared to undertake an extended campaign on behalf of Ang Nan. Nguyen Phuc Tan wanted not only to safeguard the Vietnamese position at Gia Dinh and to gain the benefits of trade with Cambodia, but also to counter Siamese influ- ence by nurturing the ambitions of friendly Khmer princes. Initial Vietnamese victories sent Kèv Fa II to the Siamese border, but the sudden death of Ang Tan left the pro-Vietnamese faction of the Khmer royal family in the less-experienced hands of Ang Nan. Siamese assistance reinvigorated Kèv Fa II’s cause, and soon Kèv Fa II counterattacked against the Vietnamese and their Cambodian allies. Vietnamese reinforcements arrived and the fighting continued. When Kèv Fa II died in 1677, his half-brother became king as Chei Chéttha III. Meanwhile, Ang Nan had proclaimed himself the “second king.” The result of this turmoil was the partitioning of the kingdom between Chei Chéttha III in the north and west, supported by Siam, and Ang Nan in the east and south, supported by the Vietnamese. The wars that ensued between Chei Chéttha III and Ang Nan con- tinued beyond Nguyen Phuc Tan’s lifetime and entrenched the Siamese and the Vietnamese as regular participants in Khmer politics. Vietnamese involvement in Cambodian affairs started with the calculations of a Khmer king, Chei Chéttha II, who viewed the Vietnamese as a relatively non- threatening ally against Siamese domination. Granting Nguyen Phuc Nguyen’s request to collect revenue at Prei Nokor and Kampong Krabei, on the far eastern edge of the kingdom, where Chinese and Vietnamese had already begun to settle, was a plausible means to keep interested and involved a distant ally distracted by more serious matters elsewhere. Nguyen Phuc Nguyen’s daughter, Ngoc Van, anchored a Vietnamese presence at the heart of the Khmer kingdom for forty years. She exercised her skill in navigating Khmer royal politics and in promoting the interests of her family until the first Vietnamese expedition in 1658, after which she is no longer mentioned in any surviving records. In the 1670s, with the end of the Trinh wars and with appeals for intervention by Khmer princes, Nguyen Phuc Tan analyzed a frontier problem without precedent in Vietnamese historical experience. Until then, Vietnamese frontiers had always been mountain passes or rivers or places where the ever-present western mountains ran out into the sea. But here there were no western moun- tains, no mountain passes, no transverse rivers, nothing but a vast deltaic plain through which the branches of a great river flowed out to the sea. The first moves, made by Nguyen Phuc Nguyen, were methods of establishing relation- ships and influence that had been traditional with upland chieftains: a marriage alliance and the arrival of Vietnamese settlers and soldiers. In 1658, Nguyen Phuc Tan had exercised another mode of action that had been used for centuries with the Chams: an expedition to temporarily seize and plunder the capital of a neighboring kingdom. In the 1670s, however, Nguyen Phuc Tan began to view the situation in a new way. The Khmer monarchy was located in the midst of a vast plain, for which the Dong Nai and Sai Gon River basin was like an antechamber for the Vietnamese. The only means of transport were up the branches of the Mekong that came together at the center of the kingdom before branching off to the “Great Lake” (Tonle Sap) and upriver to Laos. Siam stood watching just beyond. There was no terrain to barricade a border against enemies, nor was Cambodia like Champa, a relatively vulnerable and isolated neighbor that could be kept weak by periodi- cally looting its capital. The characteristic circumstances of this new kind of frontier were clearly apparent by 1674 when the Khmer royal family was split into pro-Siamese and pro-Vietnamese factions. Nguyen Phuc Tan saw that rival Khmer princes would define the Siamese and Vietnamese spheres of influence in their country and that the next necessary step on his southern border was to ally with a Khmer prince and to cultivate clients in the Khmer royal family. Thus, by the 1670s, the Cham kingdom had been deprived of its last major seaport and pushed into a relatively arid corner, and the Khmer kingdom had been partitioned into two realms under rival kings, one a vassal of Siam and the other a vassal of the Vietnamese. Furthermore, the Vietnamese had established a position at modern Saigon and Cholon that would never be relinquished and that was destined to become the largest of all Vietnamese cities.