The official history of Laos as introduced in government textbooks is conventionally traced to the establishment of the kingdom of Lan Xang by Fa Ngum in 1353. This is a relatively conservative date to begin the history of the nation, providing a contrast to the course taken by Thai historiography (which reaches back implausibly far into proto-history). By the 14th century, when this “official history” begins, the speakers of early Lao-related languages had probably developed a reasonable base of population among the prior inhabitants of Laos over the prior century or two.
The earlier inhabitation of the land by peoples such as the Mon kingdom of Dvaravati and Proto-Khmer peoples was given a great deal of emphasis in the histories of Laos written during the French colonial period. However, post-colonial historiography has instead sought to represent all peoples of Laos as equally “indigenous”, relating the early history in terms of a complex interaction with the more ancient Cambodian kingdoms to the south, and praising the Proto-Khmer as Lao nationalists for their heroism and modern struggles against the French and Americans.
It is generally assumed that, as late as the 16th century, King Photisarath helped establish Theravada Buddhism as the predominant religion of the country. However, this aspect of official history may now have to change given recent archaeological discoveries in Cambodia and Vietnam, showing intact Pali inscriptions as early as the 9th century.
While there can be no doubt that animism and fragments of Shiva-worship were popular in ancient Laos, evidence increasingly indicates a long, gradual process leading to the ascendancy of Buddhism (rather than a single king converting the country). The reverse also did occur, as with the historical layers of statuary and inscriptions at Wat Phu Champassak; the oldest are in Sanskrit, and worship Shiva, while the later evidence is Buddhist, subsequently reverting to animism (with the most recent statues simply depicting giant elephants and lizards, with no references to the organised religions of India, and neither Sanskrit nor Pali text).
It is significant to note that all of these official histories exclude the influence of Chinese religion in the region. In fact, the ancient Lao calendar and Thai calendar are both of Chinese origin, and do not reflect Indian cosmology. These calendars were both part of the royal religion and, apparently, part of popular religion for centuries.
In the 17th century Lan Xang entered a period of decline and the late 18th century Siam established control over much of what is now Laos. The region was divided into three dependent states centered on Luang Prabang in the north, Vientiane in the centre, and Champassak in the south. The Vientiane Lao rebelled in 1828 but were defeated, and the area was incorporated into Siam. Following its occupation of Vietnam, France absorbed Laos into French Indochina via treaties with Siam in 1893 and 1904.
During World War II, the Japanese occupied French Indochina. When Japan surrendered, Lao nationalists declared Laos independent, but by early 1946, French troops had reoccupied the country and conferred limited autonomy on Laos. During the First Indochina War, the Indochinese Communist Party formed the Pathet Lao resistance organization committed to Lao independence. Laos gained full independence following the French defeat by the Vietnamese communists and the subsequent Geneva peace conference in 1954.