Đại La (Chinese: 大羅城, means the Citadel of the Great Dike) or La (羅城, means the Citadel of the Dike) was an old name for the citadel of Hanoi during the third Chinese domination of the 7th and 8th centuries, and again in the 11th-century under Lý dynasty.
Đại La was constructed by jiedushi Gao Pian in 866. It was the seat of Tống Bình County during the Tang dynasty, and was capital of the Tĩnh Hải quân. In 1010, Lý Công Uẩn decided to move his capital away from the cramped Hoa Lư (present-day Ninh Bình). Đại La was favored because of its central and convenient location, defensible terrain and relatively dry climate. According to the Đại Việt sử ký toàn thư, a Yellow Dragon appeared near Lý Công Uẩn's ship when he passed by Đại La. The sighting was considered as greatly auspicious by his ministers. Subsequently, the citadel was renamed Thăng Long ("rising dragon").
- Bá Đang Nguyễn, Vũ Phương Nguyễn, Hoàng Vân Tạ Traditional Vietnamese architecture 2004 Page 122 "HA NOI CITADEL or to 1010 AD, the Ha Noi area already had a citadel, named Đại La which was built by the Chinese Governor. Later King Ly Thai To, the founder of the Ly dynasty, built a new citadel on the foundations of Đại La which ...
- Viet Nam social sciences Ủy ban khoa học xã hội Việt Nam - 2008 4/6 - Page 15 "The outer rampart: An earth rampart was raised in 1014, then rebuilt in 1078 and named Đại La Citadel. The name Đại La appeared many times in the historical chronicles, in 1078, 1154, 1165, 1170, 1230 and 1243."