Nanzhao intervenes frequently in the affairs of the principalities of the middle Mekong Valley in the later half of the eighth century, resulting in the occupation of Muang Sua in 809.

Nanzhao princes or administrators replace the aristocracy of Thai overlords.

Dates of the occupation are not known, but it probably ends well before the northward expansion of the Khmer Empire under Indravarman I (r. 877- 89) and extends as far as the territories of Sipsong Panna on the upper Mekong.