At the end of 1009, at Hoa Lu (Ninh Binh province), Ly Cong Uan ascended the throne, taking the name King Ly Thai To, establishing the Ly Dynasty. Next year he moved the capital to Dai La Citadel (Hanoi) and renamed it Thang Long (Rising Dragon). on the foundation of the Dai La Citadel, the King built a new capital that was circumscribed the three rivers: the Red River to the east, the To Lich River to the north and west, and the Kim Nguu River to the south. The Royal Enclosure, comprising, among other things, the royal palaces and the Court Hall, was surrounded by a brick fortress. Outside the Royal Enclosure was the dwelling place of ordinary people, which was divided into various guilds specializing in agriculture, handicrafts, trade, etc. Each guild had a separate location or several guilds shared one place. The Royal Enclosure and the civilian settlement formed the Royal Capital, which was surrounded by a rampart built on the dikes of the three rivers mentioned above. Thus, the dikes constituted part of the rampart while the rivers served as moats protecting the capital.
A number of religious structures were built in the civilian settlement of the Capital: the Dong Co Temple on the bank of To Lich River (1028), the Dien Huu Pagoda (One-Pillar Pagoda) to the west of the Royal Enclosure (1049), the Bao Thien Tower next to the Luc Thuy Lake (now Sword Lake, built in 1057), and the Temple of Literature (Van Mieu) with a studying place for crown princes built in 1070. It was later turned into the National University (Quoc Tu Giam). The Military Drilling (Giang Vo) Palace located in the Royal Enclosure later became the Shooting Ground in 1170, and was situated in the southern part of the Capital.
Thus, only within a century did Thang Long become the largest and most important political, economic and cultural centre of the country. The ramparts, fortress, dikes, Royal Palace, civilian houses, other cultural and religious structures blended with the natural surroundings and gave the capital its unique splendor and grace.
In its heyday, the Ly Dynasty promoted national construction and defense on a large-scale, thus commencing the era of Dai Viet civilization. Together with the people throughout the country, the inhabitants of Thang Long had contributed a great deal to the development of that civilization.
The two most outstanding personalities of the Ly Dynasty were General Ly Thuong Kiet and Queen Y Lan. General Ly Thuong Kiet (1019-1105), born in Thai Hoa Guild on the southern bank of West Lake, was the organizer and leader of the successful resistance to the Song invaders from China (1075-1077). Queen Y Lan (?–1117), whose surname was Le, was born in Sieu Loai village (present Duong Xa Commune, Gia Lam District) and became a queen very adept in national administration. She designed many policies to develop agriculture and to improve the living conditions of the populace, especially the poor.