In 1767, the Burmese also razed Ayutthaya, but the Siamese quickly rebuilt their kingdom downriver from Ayuthaya near Bangkok, and within a decade had retaken its territory, and were preparing to expand eastwards. 20,000 Siamese soldiers set out for Vientiane in 1778, devastating the city and dragging hundreds of prisoners back to Thailand, as well as the kingdom's precious Pha Bang image. Champasak and Vientiane were reduced to vassal states and Louang Phabang brought into an unequal alliance.

Over the next century, Siam and Vietnam jockeyed for control over the fragmented Lao muang, with the Lao territories eventually forming a buffer zone between the two powers. This balancing act was upset, however, by the arrival of the French.