Relations between Cambodia and Vietnam date back to when
Chey Chettha II, in order to balance the influence of the Siamese forces, which had devastated the previous capital at
Longvek during the reign of his father, had struck an alliance with Vietnam and married Princess
Nguyễn Phúc Ngọc Vạn, a daughter of Lord
Nguyễn Phúc Nguyên, in 1618. In return, the king had granted the Vietnamese the right to establish settlements in Mô Xoài (now
Bà Rịa), in the region of
Prey Nokor—which they colloquially
referred to as
Sài Gòn, and which later became
Ho Chi Minh City. Vietnamese settlers first entered the Mekong and the Prey Nokor area (later Saigon) from the 1620s onward. The region then as now is known to the Cambodians as
Kampuchea Krom but by cession and conquest (Vietnamese expansion to the South, dubbed
Nam Tiến), the area came under Vietnamese control. Under the reign of
Chey Chettha II, Cambodia formally ceded the eastern portion to the
Nguyễn lords. Koxinga's son
Zheng Jing sent a Chinese commander called Piauwja by the Dutch (Xian Biao 先彪 or Biaoye 彪爷 in Chinese) with hundreds of troops to Cambodia in February 1667 to the court of Cambodian King Paramaraja VIII. Piauwja received the title of
Shahbandar of the Chinese community of Cambodia from the King. Piauwja massacred 1,000 Vietnamese men, women and children in Cambodia on behalf of the Cambodian king, who wanted to break free of Vietnamese influence. Piauwja also demanded that the Dutch pay him compensation for confiscating his ships in a naval blockade. Pieter Ketting, the
Dutch East India Company's representative in Cambodia only offered to pay 1,000
taels to Piauwja when an advisor to the Cambodian King said he should pay 2,000 taels. Piauwja in response then demanded Ketting pay 6,000 taels, as compensation for a debt that another Chinese merchant working for the Dutch in Batavia owed him. Ketting refused and tried to bribe Cambodian officials to help him, but Piauwja forced Ketting to pay 4,837 taels by seizing Dutch hostages. The Schelvis, another Dutch ship arrived at Cambodian capital's shoreline on the river's mouth, but the river banks low water level rendered the range of the Dutch cannons on the ship useless. The Cambodians forbade fighting between Koxinga's forces and the Dutch on Cambodian waters, so Piaujwa instead attacked the Dutch East India company outpost on land on July 9-10, fatally wounding a Dutch surgeon and killing Ketting immediately along with 3 servants. Jacob van Wijckersloot only survived by escaping to the jungle and hiding for days before reaching the Schelvis and documenting what happened. On 28 October, 1667, the Cambodian King sent a letter to the Dutch in Batavia apologising for the incident, and falsely claiming he executed Piauwja, and arrested three Dutch company employees who he said helped Piauwja against their fellow Dutch. He sent the three arrested Dutch back to Batavia, but Piauwja was in fact alive and was still working for Koxinga in the 1670s, raiding the Qing in Guangdong. Piauwja had also looted all the silk and silver on the Dutch ship Schelvisch before leaving. His name was also written as Pioja by the Dutch. Another account said Piauwja came with 3,000 Chinese troops at Oudong. With the unification Vietnam under Emperor
Gia Long, the Court of Huế asserted its hegemony in 1813 and sent 10,000 troops to Phnom Penh. The Cambodian court was split into rival factions vying for power and some members of the Cambodian royal sought the support of the Vietnamese, thus implanting Vietnamese power within the kingdom. Favors were granted to allow more Vietnamese settlers and by the reign of Emperor
Minh Mạng, Vietnam chose to impose its rule directly, relegating the Cambodian court to a minor role. Administrative renaming of town and provinces was carried out while Vietnamese customs were forced upon the Cambodian populace. The heavy-handed policies stirred resentment among the Cambodian populace, provoking protracted insurgency and unrest. Vietnam was forced to withdraw, accepting the restoration of the royal candidate Ang Duong as the Cambodian king. Vietnam nonetheless joined Siam to hold Cambodia in joint vassalage. In 1880 with the establishment of the
French colonial administration, Cambodia joined Vietnam as part of
French Indochina, the status to Vietnamese residents in Cambodia was formally legalized. Over the next fifty years, large numbers of Vietnamese migrated to Cambodia. Population censuses conducted by the French recorded an increase in the Vietnamese population from about 4,500 in the 1860s to almost 200,000 at the end of the 1930s. When the
Japanese invaded Indochina in 1940, Vietnamese nationalists in Cambodia launched a brief but unsuccessful attempt to attack the French colonial administrators. With independence in 1954, Cambodia legislated a citizenship law based on knowledge in the Khmer language and national origin; this effectively excluded most Vietnamese and
Chinese Cambodians. At the grass root level, Vietnamese also faced occasional cases of violent intimidation from the Cambodians. During a
Sangkum congress in 1962, politicians debated on the issue of citizenship on Cambodia's ethnic minorities and a resolution was passed not to grant naturalization of Vietnamese residents. When
Lon Nol assumed power in 1970, the
Khmer Republic government launched a propaganda campaign to portray the ethnic Vietnamese as agents of the
Vietcong. About 30,000 Vietnamese were arrested and killed in prison, while an additional tens of thousands fled to Vietnam. Five years later in 1975 when the Khmer republic met its demise at the hands of the
Khmer Rouge, fewer than 80,000 Vietnamese remained in Cambodia. The Khmer Rouge proceeded to expel close to three quarters back to Vietnam; the remaining 20,000 were classified as mixed Vietnamese and Khmer descent and were killed by the regime. By the time
Vietnamese troops entered Cambodia in 1979, virtually all of Cambodia's Vietnamese population were either displaced or killed. Vietnam established a new regime known as the
People's Republic of Kampuchea (PRK), and Vietnamese advisers were appointed in the new government administration. In 1983, the PRK government formulated an official policy to encourage former Vietnamese residents to return and settle in Cambodia. Even Vietnamese immigrants who had no family ties to Cambodia came to settle in the country, as there was little border control to limit Vietnamese migrants from entering the country. The Vietnamese were recognized as an official minority under the PRK regime, and Overseas Vietnamese Associations were established in parts of Cambodia with sizable Vietnamese populations. The PRK government also identity cards were issued to them until the withdrawal of Vietnamese troops in 1990. Vietnamese migrant workers started to arrive from 1992 onward due to the creation of new job opportunities by the
UNTAC administration. At the same time, the UNTAC administration allowed the opening of political offices and political parties such as
FUNCINPEC and the
BLDP began to propagate anti-Vietnamese sentiments among the populace to shore up electorate support in the
1993 general elections. In November 1992, the Khmer Rouge which controlled northwestern parts of Cambodia, passed a resolution to target systematic killings of Vietnamese soldiers and civilians. The first guerrilla-style attacks by the Khmer Rouge on Vietnamese civilians started in December 1992, and Khmer Rouge soldiers justified the killings by claiming that some of the civilians were Vietnamese soldiers in disguise. The spate of killings by Khmer Rouge prompted some 21,000 ethnic Vietnamese to flee to Vietnam in March 1993. In August 1994, the
National Assembly of Cambodia introduced an immigration law which authorized the deportation of illegal immigrants. The
UNHCR assessed the law as singling out and targeting Vietnamese migrants in Cambodia; the Cambodian government had to reassure the international community that no mass deportations of Vietnamese refugees would be implemented. Meanwhile in the remote northwest, the Khmer Rouge continued to carry out sporadic attacks on Vietnamese civilians. The Khmer Rouge formally surrendered to the government in 1999 but ethnic Vietnamese continued to face discrimination in Cambodia afterwards, both as physical intimidation from the general population and administrative threats by local authorities. Anti-Vietnamese are familiar rallying cries from politicians in campaigns during the general elections and become even more acute when disputes flared in the news between the two countries. ==Demographics==