Nam tiến (Vietnamese: Nam tiến, lit. "south marching") refers to the southward expansion of the territory of Vietnam from the 11th century to the mid-18th century. The territory of Vietnam was gradually expanded to the South from its original heartland in the Red River Delta. After nearly 700 years, Vietnam's territory was increased by three times and almost had the current shape.
The direction of expansion was to the south because Annam, as Vietnam was known at that time, was surrounded by the sea to the East, by a mountainous area to the West, and by a powerful country to the North, China. Vietnam annexed all of Champa and the Mekong Delta region of Cambodia.
- Nguyen The Anh, Le Nam tien dans les textes Vietnamiens, in P.B. Lafont; Les frontieres du Vietnam; Edition l’Harmattan, Paris 1989