After an unpleasant stay in Bangkok for the funeral of King Rama III in 1825, Anu Chao returned to Vientiane and organized for rebellion. Believing a false rumor that the British were preparing to attack Siam, he led his armies toward Bangkok, and he managed to get within three days of the Siamese capital by pretending to be rushing to the defense of Siam against the British. His plans for Lao independence leaked out, however, and the Siamese were prepared for battle.
After receiving inadequate assistance from the Vietnamese, Anu was forced to flee into the forests, but he was captured by a second Siamese expedition and brought to Bangkok, where he was displayed in an iron cage and punished before he succumbed.
The Siamese, in a counterattack, captured and sacked Vientiane and transported most of the population of the central Mekong region across the river into what was later to become northeastern Thailand. By 1828 the rebellion had been quelled. An estimated 24,000 Laotians perished as did some 7000 Siamese. With the collapse of Anu's rebellion, the independence of Vientiane came to an end.