Story: Historian Le Van Lan

The Ho Dynasty Citadel draws visitors with its intriguing history and impressive architecture

The stone blocks used to build the citadel's walls and gates weighed an average of 10 to 15 tons, with some weighing up to 26 tons

In 1397, three years before being crowned Emperor and founding the Ho Dynasty (1400–1407), Chief Minister Ho Quy Ly commanded Do Tinh (also called Do Man), a Minister of the Imperial Ministry of Personnel, to supervise the construction of a citadel near An Ton Mountain, in modern-day Vinh Loc district, Thanh Hoa province. It was initially named An Ton before being renamed Tay Do Citadel to serve as the western capital of imperial Vietnam.

According to reliable historical sources, the construction of the citadel was completed within the first three lunar months of 1397. It was roughly square-shaped, with each side measuring nearly 900 meters long and around five meters high. The bases of the citadel’s trapezoidal cross section were around nine meters and 37 meters, respectively, with about 25,000 cubic meters of building stones and 100,000 cubic meters of clay, forming a nearly-square area of more than 140 hectares. Inside the citadel lay a complex of palaces, court halls, temples, shrines, “ngu dao” (a walking lane used exclusively by the Emperor), and a huge stone dragon statue that symbolized the absolute power of the royal dynasty. The citadel was considered a masterpiece that exceeded the imaginations of contemporary royals, courtiers, and the common people.

After more than six centuries, ancient walls and archways remain solid

The citadel received further praise as every large block used to build its walls and gates weighed an average of 10 to 15 tons, with the heaviest blocks weighing up to 26 tons. Massive rocks were chiseled into smooth blocks at the “mo” (crafting site) at the foot of An Ton Mountain. How the builders were able to transport these blocks over a distance of more than two kilometers and stack them without any cementing agent remains a mystery. After centuries spent watching over Thanh Hoa, the walls and archways remained solid, inspiring historians and scientists to try and figure out how the citadel was built.

Another construction breakthrough was the citadel’s location. It was tucked between the Ma and Buoi rivers and shielded by many mountains, including Don Son, Hac Khuyen, Xuan Dai, Trac Phong, Tien Sy, Kim Ngo, Nguu Ngoc, and Elephant Mountain. This arrangement formed a large “inner citadel” that was surrounded by a moat up to 50 meters wide. The outer citadel (or “La Thanh”) had a perimeter of more than 10 kilometers, surrounded by an earth wall with dense bamboo planted on top. Together with the neighboring mountains, this created a closed fortification. This defense structure continued the sophisticated “bamboo citadel” tradition of the Co Loa (3rd century BC) and Hoa Lu (10th century) eras.

A question has long been raised, however. Why did the An Ton – Tay Do Citadel (commonly called the Citadel of the Ho Dynasty) prove useless during the 1407 Ming invasion despite its marvelous aspects? After it fell to invaders, the citadel became their dangerous base. Troops were sent from there to suppress the Lam Son patriotic movement of Le Loi – Nguyen Trai during its infancy. Even after the movement grew, Tay Do Castle remained an undefeated enemy base. The castle’s security remained unbroken until the Lam Son Uprising succeeded in defeating the Ming invaders at the end of 1427.

An stone arch

Many questions were answered after UNESCO recognized the Ho Dynasty Citadel as a World Cultural Heritage site in 2011. It was only through a contemporary viewpoint, after a difficult period of history, that the feats of construction, architecture and planning of the ancient citadel could be properly recognized. Its unique architectural style, rarely seen regionally as well as globally, definitely met the second and fourth criteria for recognition as a World Cultural Heritage by UNESCO. It is considered an outstanding example of a type of architectural complex and exhibits an important interchange of human values over a span of time or within a cultural area of the world.

The Ho Dynasty Citadel has become a kind of “holy grail” site where archaeologists can learn about and more fully appreciate this masterpiece’s value. At the same time, it has become a captivating tourist attraction. It would be even better if the heroic imprints and historical lessons linked to this site continued to resonate, just like the words of General Ho Nguyen Trung, which rang out in 1405: “I’m not afraid of fighting, but of the lack of people’s support”. That would surely honor the multifaceted values of the citadel – one of Vietnam’s ancient capitals – even more.