The expansion of the Viets had eventually caused the northwestern part of the so-called Khmer Empire to fall from imperial Chinese control.

When the Le emperor Le Long Dinh dies in his twenties, a court general named Ly Cong Uan takes the opportunity to seize the throne.

This event is regarded as the beginning of a golden era in Vietnamese history, with great dynasties following one another.

Ly (commonly called Ly Thai To—the Founding Emperor) changes the country's name to Dai Viet, establishes the capital in present-day Hanoi and calls it Thang Long (Ascending Dragon) under the pretext of seeing a dragon when he was touring the area.