Treaty of Saigon
In 1862, the Nguyễn dynasty signed the Treaty of Saigon. It agreed to surrender Saigon and 3 southern provinces to France which were to become known as Cochinchina. Some authors point to the dynasty's need to put down rebellions in the North as a reason territories were ceded in the South. Regardless of the reason, the regular army was to withdraw from the surrendered provinces, leaving the popular resistance movement to the French.