The traditional capital of Lan Xang was at Luang Prabang until it was moved in 1560 by King Setthathirath to better administer the growing population and provide security in facing threats from Burma and Siam.

Lan Xang entered a Golden Age during the reigns of Visunarat (1501–1520) and Sourigna Vongsa from (1637–94), during these times the cultural and economic power of the kingdom were at their greatest.

From 1941 to 1945 Thailand exploited France's weakness during World War II to acquire Champasak and other Lao lands on the right bank of the Mekong.

In 1946 Champasak was ceded back to France and Chao Boun Oum remitted all claims to an independent kingship in order to unify Laos.

Geographic isolation and frequent warfare produced periods where the Phuan kings tried to assert more authority, but the region remained only a key vassalage for surrounding kingdoms.