[citation needed] Bassac and the neighboring principalities of Attapeu and Stung Treng emerged as power centers under what was later to be described as the Mandala Southeast Asian political model.

[citation needed] At the beginning of the 19th century, and ignoring the worldwide agricultural disaster accompanying the 1816 Year Without a Summer, Bassac was said to be on a prosperous trade route as the outlet for cardamon, rubber, wax, resin, skins, horns, and slaves from the east bank to Ubon, Khorat, and Bangkok.

The 1893 treaty called for a 25-kilometre (16 mi) wide demilitarized zone along the Right Bank, which made Siamese control impossible.

Lack of clear chains of authority resulted in turmoil in the whole region, and in what was known to the Siamese side as the "Holy Man's Rebellion".

[1]: image 22  Following legal action against captured local leaders of the movement, the Thai government considered the case of the rebellion closed.

[1]: image 15  The right-bank dependencies were absorbed into the Siamese Northeast Monthon, Isan (มณฑลอีสาน), and the House of Na Champassak continued to rule autonomously.

Despite historical claims by Cambodia, Champassak lost jurisdiction over the province of Stung Treng and in return regained the city of Champasak.