After the march in 1653 of Lord Nguyen Phuc Tan, Champa was no longer an obstacle for Cochinchina in the process of money going south. Lord Nguyen began to pay attention to the rich southern land, much larger than the narrow central strip of land. In the middle of the seventeenth century, the Vietnamese exiles from the five Quang regions by various means came to the land of Dong Nai and Gia Dinh. Together, they fought hard to exploit the land and establish Vietnamese villages on the land of Thuy Chan Lap, before Lord Nguyen merged it into the territory of Cochinchina. During the sixteenth and seventeenth centuries, Southern Vietnam was nominally still under the management of Chenla (although very loosely), the newly established Siam kingdom also raised ambitions to expand its territory. Therefore, the Nguyen lord's foreign policy towards neighboring countries (especially Chan Lap and Siam) contributed to speeding up the process of merging the lands explored by the Vietnamese into the territory of Cochinchina.

Cochinchina, Chan Lap, Siam, discovery, Southern region