[1] In 1840, the Cambodian queen Ang Mey was deposed by Vietnamese; she was arrested and deported to Vietnam along with her relatives and the royal regalia.

Spurred by the incident, many Cambodian courtiers and their followers revolted against the Vietnamese rule.

[2] The rebels appealed to Siam who supported another claimant to the Cambodian throne, Prince Ang Duong.

Rama III responded and sent Ang Duong back from exile in Bangkok with Siamese troops to install him on the throne.

[4] Trương Minh Giảng, the Governor-General of Trấn Tây (Cambodia), was called back.