Vietnam's identity has been shaped by long-running conflicts, both internally and with foreign forces. In 111 BC, China's Han dynasty conquered northern Vietnam's Red River Delta and the ancestors of today's Vietnamese. Chinese dynasties ruled Vietnam for the next 1,000 years, inculcating it with Confucian ideas and political culture. In 939 AD, Vietnam achieved independence under a native dynasty. After 1471, when Vietnam conquered the Champa Kingdom in what is now central Vietnam, the Vietnamese moved gradually southward, finally reaching the rich Mekong Delta, encountering there earlier settled Cham and Cambodians. While Vietnam's emperors reigned ineffectually, powerful northern and southern families fought civil wars in the 17th and 18th centuries.

French Rule and the Anti-Colonial Struggle
In 1858, the French began their conquest of Vietnam starting in the south. They annexed all of Vietnam in 1885, but allowed Vietnam's emperors to continue to reign, although not actually to rule. In the early 20th century, French-educated Vietnamese intellectuals organized nationalist and communist-nationalist anti-colonial movements. Japan's occupation of Vietnam during World War II further stirred nationalism.

Vietnamese communists under Ho Chi Minh organized a coalition of anti-colonial groups, the Viet Minh, though many anti-communists refused to join. After Japan stripped the French of all power in March 1945, Ho Chi Minh announced the independence of the Democratic Republic of Vietnam on September 2, 1945.

North and South Partition
France's post-World War II unwillingness to leave Vietnam led to failed talks and an 8-year guerilla war between the communist-led Viet Minh on one side and the French and their anti-communist nationalist allies on the other. Following a humiliating defeat at Dien Bien Phu in May 1954, France and other parties, including Britain, China, the Soviet Union, and the United States, convened in Geneva, Switzerland for peace talks. On July 29, 1954, an Agreement on the Cessation of Hostilities in Vietnam was signed between France and the Democratic Republic of Vietnam. The United States observed, but did not sign, the agreement. French colonial rule in Vietnam ended.

The 1954 Geneva agreement provided for a cease-fire between communist and anti-communist nationalist forces, the temporary division of Vietnam at approximately the 17th parallel, provisional northern (communist) and southern (noncommunist) zone governments, and the evacuation of anti-communist Vietnamese from northern to southern Vietnam. The agreement also called for an election to be held by July 1956 to bring the two provisional zones under a unified government. However, the South Vietnamese Government refused to accept this provision. On October 26, 1955, South Vietnam declared itself the Republic of Vietnam.

After 1954, North Vietnamese communist leaders consolidated their power and instituted a harsh agrarian reform and socialization program. In the late 1950s, they reactivated the network of communist guerillas that had remained behind in the south. These forces--commonly known as the Viet Cong--aided covertly by the north, started an armed campaign against officials and villagers who refused to support the communist reunification cause.

American Assistance to the South
In December 1961, at the request of South Vietnamese President Ngo Dinh Diem, President Kennedy sent U.S. military advisers to South Vietnam to help the government there deal with the Viet Cong campaign. In the wake of escalating political turmoil in the south after a 1963 generals' coup against President Diem, the United States increased its military support for South Vietnam. In March 1965, President Johnson sent the first U.S. combat forces to Vietnam. The American military role peaked in 1969 with an in-country force of 534,000. However, the Viet Cong's surprise Tet Offensive in January 1968 deeply hurt both the Viet Cong infrastructure and American and South Vietnamese morale. In January 1969, the United States, governments of South and North Vietnam, and the Viet Cong met for the first plenary session of peace talks in Paris, France. These talks, which began with much hope, moved slowly. They finally concluded with the signing of a peace agreement, the Paris Accords, on January 27, 1973. As a result, the south was divided into a patchwork of zones controlled by the South Vietnamese Government and the Viet Cong. The United States withdrew its forces, although U.S. military advisers remained.

Reunification
In early 1975, North Vietnamese regular military forces began a major offensive in the south, inflicting great damage to the south's forces. The communists took Saigon on April 30, 1975, and announced their intention of reunifying the country. The Democratic Republic of Vietnam (north) absorbed the former Republic of Vietnam (south) to form the Socialist Republic of Vietnam on July 2, 1976.

After reunification, the government confiscated privately owned land and forced citizens into collectivized agricultural practices. Hundreds of thousands of former South Vietnamese Government and military officials, as well as intellectuals previously opposed to the communist cause, were sent to re-education camps to study socialist doctrine.

While Vietnamese leaders thought that reunification of the country and its socialist transformation would be condoned by the international community, this did not happen. Besides international concern over Vietnam's internal practices, the Vietnamese invasion of Cambodia in 1978 and its growing tight alliance with the Soviet Union appeared to confirm suspicions that Vietnam wanted to establish hegemony in Indochina.

Vietnam's invasion of Cambodia also heightened tensions that already existed between Vietnam and China. Beijing, which had long backed the Khmer Rouge regime in Cambodia, retaliated in early 1979 by initiating a border war with Vietnam.

Vietnam's tensions with its neighbors and its stagnant economy contributed to a massive exodus from Vietnam. Fearing persecution, many Chinese in particular, fled Vietnam by boat to nearby countries. Later, hundreds of thousands of other Vietnamese nationals fled as well, seeking temporary refuge in camps throughout Southeast Asia.

The continuing grave condition of the economy and the alienation from the international community became focal points of party debate. In 1986, at the Sixth Party Congress, there was an important easing of communist agrarian and commercial policies.