The early inhabitants of the area apparently were Negritos. Some 4,000 years ago Austronesian (Indonesian) migrants from the north were moving into the area that is now north Vietnam. Later, Austroasiatic (Mon-Khmer and Malayo-Polynesian) peoples arrived. Then, about 2,500 years ago Viet (Yueh) and Tai peoples moved down from southern China. Out of this mixture of genes, languages, and cultures arose Van Lang, considered to have been the first Vietnamese kingdom. In mid-third century B.C. Van Lang was overrun by and incorporated into another state to the north, forming the kingdom of Au Lac. Then Au Lac was incorporated into an even larger and more powerful state: Nam Viet (Nan Yueh in Chinese), centered on Canton. Local leadership and culture were little disrupted in the Red River Delta, although new cultural elements entered from the north. In 111 B.C. the region was incorporated into the expanding Han Empire in China and the Red River Delta was part of the Chinese empire for a thousand years. Local hereditary leadership was used by both Nam Viet and early Han rulers, but as infrastructure and more intensive production techniques developed, pressure increased for more complete Sinicization of local culture and administration. In A.D. 39 the Trung sisters led the traditional local elite in a popularly supported revolt that flourished briefly but was suppressed in A.D. 43, ending hereditary leadership. The new hybrid elite of the Red River Delta kept and developed a sense of regional identity; the local language and many non-Chinese customs were retained. Revolts came periodically until A.D. 939 when independence from Chinese rule was achieved, although China would remain a military threat and a continuing source of cultural influence. What is now central Vietnam was then the kingdom of Champa. The Cham spoke an Austronesian language, had a powerful Indian influence on their culture and political organization, and also had a strong maritime orientation. Over the next six centuries Vietnam displaced or assimilated the Cham and extended Vietnamese territory down the coast to the plains and foothills east of Saigon, which they took and occupied during the seventeenth century. The Vietnamese then expanded at the expense of Cambodia, settling the western Mekong Delta in the eighteenth century and the eastern portion in the nineteenth. But between 1859 and 1883 all of Vietnam fell under French colonial control. South Vietnam (called Cochinchina) was a French colony; central Vietnam (called Annam) and northern Vietnam (called Tonkin) became protectorates. Together with Cambodia and Laos, they constituted French Indochina. A public school system established by the French in 1908 disseminated elements of Western culture in Vietnam, influencing but not destroying Vietnamese culture. In 1945 a popular revolution erupted against French rule. As this movement came under increasingly strong Communist control, however, some Vietnamese became disaffected. In 1955 Vietnam gained independence from France but was divided into the Socialist Republic of Vietnam in the northern half and the anti-Communist Republic of Vietnam in the southern half. About 900,000 Vietnamese relocated from the north to the south, while 90,000 or so others moved from south to north. A Communist-led revolution in the south evoked heavy American support for the Republic of Vietnam, adding American influence to the already heterodox southern region, and led to the invasion of the south by northern troops. After a devastating war, Communist forces in 1975 took over all of Vietnam, the foreign troops departed, and the Socialist Republic of Vietnam was established in 1976.