It was a special province with a dual system, consisting of Cambodian monarchs who reigned as puppet rulers while a Vietnamese governor resided in Phnom Penh.

Cambodian princess Ang Mey, daughter of king Chan, was crowned as de jure ruler of Cambodia in early 1835 with a Vietnamese-style ceremony.

Vietnamese offices and soldiers in Tây Thành province were assassinated by Cambodian guerillas while the governor Trương Minh Giảng had been recalled by the newly crowned emperor Thieu Tri to deal with internal rebellions.

[4] After a failed attempt to place Prince Im on the Cambodian throne in late 1841, Trương Minh Giảng committed suicide.

After reached a peace agreement with Siam, in June 1847 the Vietnamese court released all royal members of the Cambodian ruling family, transferred the government to the new independent Cambodian monarchy of king Ang Duong and withdrew their army from Cambodia, ending the Tây Thành province.