Colonial Times
In 1868, after having annexed South Vietnam as a colony and having turned Cambodia into a French protectorate, the French sent an initial expedition to Laos to investigate the Mekong trade route to China.
In 1886 France received permission from Siam largely ruling Laos to install a vice consulate in Luang Prabang. In 1887, Siam, anticipating French expansion, vacateds large parts of Laos.
In 1893 France declared the Mekong the official border between Laos and Siam. Might is right; Siam accepts the unilateral decision of big-gun France. Laos officially became a French protectorate.
However, France had only limited interest in her new possession. Paris sent Vietnamese officials to Laos to set up an administration but did little to develop the Laotian economy.
In September 1940, after France was invaded by Germany, Japanese troops occupied Indochina without meeting any resistance.
Officially the word was that the French colonial power left all military installation for the Japanese troops to use; in exchange the French colonial administration remained in office. Therefore the years of World War II brought less destruction to Laos than, for instance, to the fiercely contested Southeast Asian states of Burma and the Philippines.
In East Asia, World War II ended August 14, 1945, with the capitulation of Japan. Subsequently, France tried to re-establish herself as a colonial power in Cambodia, Vietnam and Laos.
On September 1, 1945, Laos declared its independence. France refused to accept this, and retaliated by sending troops into Laos. A guerilla war against the French colonial power started.

Independence
On July 19, 1949, France formally granted Laos independence. For almost three decades, from 1949 to 1975, the political situation in Laos was highly confusing. Three factions struggled for power: 1. Conservatives, commanding, among other forces, a 30,000-men army of the Hmong (Meo) hill tribe; 2. Neutralists, organized by Prince Souvanna Phouma; 3. Communists, lead by a feudal prince, Souphanouvang (a contradiction Marx had not anticipated).
The civil war among the three rival factions was, however, not fought as fiercely as the civil wars in Vietnam or Cambodia. Several times in three decades coalition governments were formed, including all three factions. The neutralists usually led the coalitions.
From 1964 to 1973 the US fought a secret war in Laos against Laotian communists as well as North Vietnamese troops channeling war material to the Vietcong in South Vietnam via the Ho Chi Min Trail through Laos.
After the US forces began their retreat from Indochina in 1973, the right-wing government in Vientiane was replaced by a coalition government of neutralists and the communist Pathet Lao.
In 1975, after communist troops conquered the capitals of Vietnam and Cambodia, the communist Pathet Lao gained sole power in Laos. While in Laos, too, parts of the population were detained in re-education camps, there wasn't the kind of revenge as in Cambodia. Former neutralist Premier Minister Souvanna is not even arrested, just demoted in rank to government advisor.
In the following decades Laos cultivateed a close relationship with Vietnam. The most powerful man in communist Laos, General Secretary of the Revolutionary Party of the People, Kaysone Phomvihan, is half Laotian and half Vietnamese.
In March 1991, at the fifth congress of the Revolutionary People's Party, far-reaching changes of the economic structure of the country were decided. As in China and Vietnam, private business, free-market competition and foreign investment are permitted in order to accelerate the economic development of the country. However, as in China and Vietnam, political leaders are not inclined to share power in a multi-party system.