In the nineteenth century, a renewed struggle between Siam and Vietnam for control of Cambodia resulted in a period when Cambodia became the Tây Thành Province of Nguyễn Vietnam, during which Vietnamese officials attempted to force the Khmers to adopt Vietnamese customs. This led to several rebellions against the Vietnamese and appeals to Thailand for assistance. The Siamese–Vietnamese War (1841–1845) ended with an agreement to place the country under joint suzerainty. This later led to the signing of a treaty for French Protection of Cambodia by King Norodom Prohmborirak.