Đại La (Chinese: 大羅城; pinyin: Dàluóchéng), means the Citadel of the Great Dike, or La Thành (羅城, means the Citadel of the Dike) was an ancient fortified city in present-day Hanoi during the third Chinese domination of the 7th and 8th centuries,[1] and again in the 11th-century under Lý dynasty.
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.
[5] The city had enclosed guard posts, courtyards, some thousand buildings, a water sewerage system, and a 4,5-meter high dike.
Excavations from 2002 to 2009 in an area covered 19,000 square meters recovered large quantities of artifacts, probably dated through the period of occupation, i.e. 7th–10th century.