Lê Văn Duyệt
Lê Văn Duyệt had been a powerful mandarin of southern Vietnam and exerted his influence over Cambodia. After his death in 1832, Emperor Minh Mạng condemned Lê Văn Duyệt to the charge of treason and prosecuted his associates. Lê Văn Khôi, the adoptive son of Lê Văn Duyệt, led the Lê Văn Khôi revolt in May 1833 and took Saigon. King Rama III then took thw opportunity to end the Vietnamese influence in Cambodia and in the region. Rama III initiated the Siamese campaign to bring Prince Ang Em to the Cambodian throne and to take Saigon.