In 1690, however, Lan Xang fell prey to a series of rival pretenders to its throne, and, as a result of the ensuing struggles, split into three kingdoms--Louangphrabang, Vientiane, and Champasak. Muang Phuan enjoyed a semi-independent status as a result of having been annexed by a Vietnamese army in the fifteenth century, an action that set a precedent for a tributary relationship with the court of Annam at Hué.

Successive Burmese and Siamese interventions involved Vientiane and Louangphrabang in internecine struggles. In 1771 the king of Louangphrabang attacked Vientiane, determined to punish it for what he perceived to be its complicity in a Burmese attack on his capital in 1765. The Siamese captured Vientiane for the first time in 1778-79, when it became a vassal state to Siam. Vientiane was finally destroyed in 1827-28 following an imprudent attempt by its ruler, Chao Anou, to retaliate against perceived Siamese injustices toward the Lao.

The disappearance of the Vientiane kingdom and the weakened condition of Louangphrabang led to a period of direct Siamese presence on the left bank of the Mekong and to the virtual annexation of Xiangkhouang and part of Bolikhamxai by the Vietnamese. The Siamese also soon became more directly involved with the Kingdom of Louangphrabang, whose ruler, Manta Thourath (r. 1817-36), had sought to preserve neutrality in the conflict between Siam and Vientiane. The Siamese intervention was caused by an appeal by King Oun Kham (r. 1872-94) for help in clearing his northeastern territories of the Hô (Haw), bands of armed horsemen who had fled the bloody Manchu campaign to pacify Yunnan.

The last major migration into Laos in the nineteenth century was that of the Hmong (see Glossary). Accustomed to growing crops of dryland rice and maize at the highest elevations in mountainous southern China, where they had lived for centuries, the Hmong practiced a peaceful coexistence with their neighbors at lower elevations. Their major interaction occurred in selling their chief cash crop, opium.

Data as of July 1994