Citadel of the Ho Dynasty

Three months. That is the number to hold on to here.

In three months, workers finished a citadel with stone walls 3.5 kilometers around. Some of its blocks weighed more than 10 tons. There was no cement, no mortar and no modern machinery. There was only human labor, with workers called up from many regions across the country. They were brought here early in 1397. The citadel's stone walls have stood for more than 600 years. They came through wars and many seasons of rain and sun, and they are still standing today.

This is the Citadel of the Hồ Dynasty, known in Vietnamese as Thành Nhà Hồ. It is also called Tây Đô. It lies in the Vĩnh Lộc area of Thanh Hóa province.

The man who ordered it built was Hồ Quý Ly, a high official who held the real power at the end of the Trần dynasty. He chose this land according to the principles of feng shui. The citadel sits between two rivers, the Mã and the Bưởi, with mountains guarding all four sides. To the north rises Thổ Tượng, and to the south, Đốn Sơn. To the east stands Hắc Khuyển, and to the west, Ngưu Ngọa. He named the new capital Tây Đô, the Western Capital, to set it apart from Thăng Long, the Eastern Capital. Thăng Long is the city now called Hanoi. In 1400, Hồ Quý Ly deposed the Trần emperor and founded the Hồ dynasty. But the dynasty lasted only seven years. In 1407, armies of the Ming swept down from the north and destroyed it. The Ming were the dynasty then ruling China.

The citadel lost its role as a capital and lay abandoned for centuries. But the stone walls stayed where they were.

On June 27, 2011, at a session of the World Heritage Committee in Paris, UNESCO inscribed the citadel as a World Cultural Heritage site. It was the fifth site in Vietnam to receive that recognition. UNESCO listed it under two criteria. The first concerns the exchange of human values. Through its city planning and architecture, the citadel shows the ideas of Neo-Confucianism at the end of the 14th century. The second concerns exceptional architecture. The citadel is an outstanding example of a new style of royal capital in Southeast Asia. It was both a center of political power and a military fortress, and it used dry stone building without mortar on a large scale.

The secret of its 600 years lies in the way the stones were laid. The old masons cut each block square, then set the blocks in staggered courses, both horizontally and vertically. That pattern creates mechanical friction between the blocks, which does all the work that mortar would do. An average block is 1.5 to 2 meters long. Some reach 6 or 7 meters. The heaviest is estimated at more than 26 tons. It is a remarkable achievement by the stonemasons of medieval Vietnam.

The South Gate is the best preserved and most striking part of the citadel. It is more than 33 meters long and nearly 10 meters high, with three arched stone doorways. The middle doorway is the largest. It is nearly 6 meters wide and nearly 6 meters high. The two side doorways are a little narrower. What stands out is the stone of the arches. Each piece was cut in the shape of a pomelo segment, and the pieces were fitted tightly together in a fan. Again, no binding material was used at all. From 2018 to 2020, the United States Ambassadors Fund for Cultural Preservation gave 92,500 US dollars to restore the South Gate.

There is one detail of the design that UNESCO singles out as a sign of a distinct identity. Capitals shaped by Chinese influence usually had a main axis running north to south. But the main axis of this citadel turns aside to line up with Đốn Sơn mountain to the south. That is where the Hồ court had the Nam Giao Altar built in 1402. At the altar, the emperor made offerings to Heaven, the most sacred rite of the old royal courts of East Asia. The turn of the axis was not a mistake. It was a deliberate choice. It shows how Vietnamese builders took architectural ideas from abroad and adjusted them to their own land and their own traditions.

Stand before the South Gate and look up at the ancient blue stone blocks, and the number comes back: three months. So many hands, shoulders and eyes measured every block. They lifted each one, set it down and checked each angle, so the whole citadel would stand without a single drop of mortar. The citadel has stood for more than 600 years. The Hồ dynasty lasted only seven. But the skill and the will of those stonemasons outlasted every dynasty and every war, and their stones are still here today.