Hoa Lư was the capital of Vietnam in the 10th and 11th centuries. It lies in Truong Yen Thuong village, Truong Yen Commune, Hoa Lu District, Ninh Binh Province, Vietnam. The area is one of ricefields broken by picturesque limestone mountains, and is approximately 90 km south of Hanoi. Together with Phat Diem Church, Tam Coc - Bich Dong, Bai Dinh Pagoda, Trang An, and Cuc Phuong, Hoa Lu is one of the most popular tourist destinations in Ninh Binh Province.
In the late 10th century, Hoa Lu was the capital as well as the economic, political and cultural center of Đại Cồ Việt, an independent Vietnamese polity founded in 968 A.D. by the local warlord Đinh Bộ Lĩnh (posthumously known as Đinh Tiên Hoàng, or "First Dinh Emperor"), following years of civil war and a violent secessionist movement against China's Southern Han Dynasty. Hoa Lu was the native land of the first two imperial dynasties of Vietnam: the Dinh founded by Đinh Tiên Hoàng, and the Early Le founded by Lê Đại Hành. Following the demise of the Le Dynasty, in 1010 Lý Công Uẩn, the founder of the Ly Dynasty, transferred the capital to Thắng Long (now Hanoi), and Hoa Lu became known as the "ancient capital."
The capital at Hoa Lu covered an area of 300 ha (3.0 km2), including both the Inner and Outer Citadels. It included defensive earthen walls, palaces, temples and shrines, and was surrounded and protected by mountains of limestone. Today, the ancient citadel no longer exists, and few vestiges of the 10th century remain. Visitors can see temples built in honor of the emperors Dinh Tien Hoang and Le Dai Hanh, their sons, and Queen Duong Van Nga, who was married first to Dinh Tien Hoang and then to Le Dai Hanh. The tomb of Dinh Tien Hoang is located on nearby Mã Yên mountain, while the tomb of Le Dai Hanh lies at the foot of the mountain.
The ancient capital of Hoa Lu was located in a flat valley between small but steep limestone mountains that created virtually impenetrable barriers to human traffic. Even today, many of the mountains are accessible only to the mountain goats that roam the area.
The 10th century rulers of Dai Co Viet took advantage of this topography in order to design enclosures that would be especially difficult to attack. In order to block the gaps between the limestone mountains, they ordered the construction of earthen walls reinforced and anchored in the soft earth by wooden stakes. In all, the capital was protected by ten sections of wall, the longest being 500m in length and the shortest 65m in length. They were approximately 10m high and 15m thick. Several sections of wall still exist and have been excavated by archeologists.
During the time it served as the capital, Hoa Lu's defenses were never actually tested by an enemy army. In 972, the king of Champa sent a fleet against Hoa Lu, but it was devastated by a storm as it tried to enter the river system from the sea and was forced to return home with great loss. In 981, two Chinese armies of the Song Dynasty invaded the Dai Co Viet with the aim of eventually working their way south and taking the capital, but they were stopped and defeated in the northern part of the country.
The ancient capital at Hoa Lu consists of two separate enclosures, the Inner Citadel which lies to the West and the Outer Citadel which lies to the East, and which includes most of the sites visited by tourists. The two citadels are separated by a limestone mountain. Both have access to the Hoàng Long ("Golden Dragon") River that runs just northwest of the capital and that, via a system of rivers, connects Hoa Lu to the sea. In the 10th century, the dwellings of the common people, as well as the markets and the storehouses connected with the river trade, were concentrated near the river.