Nguyen Hoang (1525-1613) is a historic figure who deserved particular credit for the restoration of the Later Le dynasty and set the foundation for the southward territorial expansion and the establishment of “Đàng Trong” (Southern land, the region in Central Vietnam, which was later enlarged to become Cochinchina) during the period of the Nguyen lords. He was highly appreciated in the historical documents of not only the Nguyen but also the Later Le, who were in the mutually antagonistic relationship. Ruling the region as a lord, he created a new region named Phu Yen, extending the national territory one latitude southwards. On the occasion of the 400-year anniversary of Nguyen Hoang’s death, we would like to present some explanations so as to honour him as a predecessor of great credit for the national defence and territorial expansion.