The Lao people originally occupied parts of southern China. They were gradually driven southward into the Indochinese Peninsula by the Chinese. About the 12th century, the Lao moved into the area that is now Laos, peacefully settling among the inhabitants. These native peoples included the descendants of dark-skinned aborigines and of Malay-Indonesians, who had arrived there between 500 B.C. and 500 A.D.
In 1353 Fa Ngoun united a number of small principalities along the Mekong River into the kingdom of Lan Xang. Its capital was Louangphrabang. At about this time, Theravada Buddhism was made the state religion. Lan Xang prospered during the late 14th and early 15th centuries, but then was wracked successively by internal dissension and wars with neighboring countries. Early in the 18th century, it split into the kingdoms of Louangphrabang in the north, Vientiane in the center, and Champassak in the south. Wars against Siam, Burma, Annam, and China followed. In 1828 Vientiane was conquered by the Siamese, and Louangphrabang and Champassak soon fell under the influence of their neighbors.
France began to penetrate Indochina in 1858. In 1893 the French expelled the Siamese from Laotian territory. By 1904 France had reunited the region, given it the name Laos, and made it a French protectorate. France ruled the country until Indochina was overrun by the Japanese in 1941. In 1946 French control was reestablished. The head of the ruling family of Louangphrabang, which had been allowed to retain its royal prerogatives under the French, was made king of Laos. Laos became independent within the French Union in 1949 and the country achieved complete independence in 1953.
Communist North Vietnamese invaded northern Laos in 1953 but withdrew the next year as a result of an agreement reached at the 1954 Geneva Conference. Fighting in the north between government forces and Laotian Communist rebels, called Pathet Lao, followed. The head of the Pathet Lao was Prince Souphanouvong. His half-brother, Prince Souvanna Phouma—who was premier 1951–54, 1956–58, 1960, and 1962–75—made many attempts to establish a coalition government with the Pathet Lao while waging almost continuous war against them. The United States, fearing a Communist takeover of the country, supplied much military and economic aid.
A cease-fire was arranged in 1961. The United States and other world powers met in Geneva, Switzerland, and in 1962 agreed to guarantee Laotian neutrality. A coalition government composed of the rival rightist, neutralist, and Communist factions was formed. The Pathet Lao soon withdrew from the coalition. With the help of the North Vietnamese, the Pathet Lao seized large portions of the country. The United States organized and supported private tribal and Thai armies to resist the Communists. During the Vietnamese War (1957–75), fighting between the Vietnamese Communists and the Allied forces often spread into Laos.
In 1973 a peace agreement was signed between the Laotian government and the Pathet Lao. A coalition of rightists, neutralists, and Communists was formed in 1974 with Souvanna Phouma remaining as premier. However, in 1975, after neighboring Cambodia and South Vietnam fell to the Communists, the Pathet Lao expelled all rightists and neutralists from the government and seized control of the entire country. The monarchy was abolished and a Communist regime established in its place. Souphanouvong became the country's first president; he held the post until 1986.
Laos made economic reforms in the early 1990's, allowing the creation of a very limited free market. It was admitted to the Association of Southeast Asian Nations in 1997.