In Thanh Hoa province, about 150 kilometers south of Hanoi, the remains of a 600-year-old stone fortress have guarded a secret beneath their foundations for centuries. Now, archaeologists are finally digging it up.
Vietnam’s Ministry of Culture, Sports and Tourism authorized one of the largest excavations ever attempted at the Ho Dynasty Citadel, a UNESCO World Heritage Site built in 1397 under the ruler Ho Quy Ly. The target: the Nam Giao altar complex, a ceremonial platform where Ho Dynasty kings once performed heaven-worship rituals rooted in Confucian tradition. The dig permit, Decision 3691/QD-BVHTTDL, covers 9,909 square meters across 94 individual trenches, with fieldwork running from late October 2025 through July 2026.
As of June 2026, the excavation is well underway, and the stakes are high. Earlier, smaller digs at the citadel recovered fragments of terracotta roof ornaments decorated with a thin gold-toned glaze, many shaped as dragon heads or dragon-bodied ridge tiles that once crowned palace roofs and ceremonial structures. Those earlier finds fueled expectations that a full-scale excavation of the altar zone could yield far more complete examples of Ho-era craftsmanship, potentially including intact ritual objects that have not seen daylight since the early fifteenth century.
A fortress built to last, a dynasty that didn’t
The Ho Dynasty is one of the shortest-lived ruling houses in Vietnamese history, lasting only from 1400 to 1407 before falling to a Ming Chinese invasion. But the architectural ambition of those seven years was extraordinary. The citadel’s walls, constructed from enormous limestone and laterite blocks fitted together without mortar, stretch roughly 870 meters along the north-south axis and 880 meters east to west, according to UNESCO’s site documentation. Portions still stand, making it one of the few surviving stone fortresses anywhere in Southeast Asia.
The Nam Giao altar sits south of the main fortress, following the traditional geomantic placement for heaven-worship platforms used across East Asian court cultures. In that tradition, the emperor or king ascended a tiered platform to offer sacrifices to heaven, asserting his role as the intermediary between the cosmic order and the human world. Dragon imagery was central to that symbolism. In Chinese and Vietnamese imperial iconography, dragons represented sovereign authority and celestial power, and their placement on rooflines above a heaven-worship altar would have reinforced the ruler’s claim to divine legitimacy.
Despite the citadel’s UNESCO inscription in 2011, the altar area had never been excavated at anything close to this scale. Previous digs were limited in scope, recovering fragments but leaving the deeper stratigraphy of the altar platform and its surrounding terraces largely untouched.
What the gold-glazed dragon ornaments actually are
The artifacts that have drawn the most attention are terracotta pieces finished with a gold-toned glaze, a technique that gave ceramic architectural ornaments the appearance of gilded metal. These are not solid gold objects. They are fired clay, shaped into dragon heads, serpentine bodies, and decorative ridge tiles, then coated with a glaze that catches light in a way that would have made rooflines shimmer from a distance. The technique reflects a sophisticated ceramic tradition, and the question of whether these pieces were produced locally in Thanh Hoa or imported from kilns elsewhere in Vietnam or beyond remains open.
Earlier recoveries from the citadel established that such ornaments existed at the site, but the fragments were found in limited contexts that made it difficult to determine their original placement. Were they mounted on the altar structure itself? On surrounding pavilions? On a gatehouse that no longer survives? The current excavation, with its 94-trench grid spanning nearly 10,000 square meters, is designed to answer exactly those spatial questions.
Why the trench grid matters
The sheer number of trenches is significant. In archaeological fieldwork, a dense grid of excavation units allows researchers to map the horizontal distribution of artifacts and architectural features across a large area. If gold-glazed dragon ornaments turn up concentrated around the altar platform, that pattern would support the interpretation that they were part of the altar’s original decoration or ritual furnishings. If they are scattered widely and mixed into fill layers or erosion deposits, the picture becomes more complicated, possibly pointing to destruction debris from the Ming invasion of 1407 or later disturbance from agricultural activity, weathering, or looting over six centuries.
Careful recording of soil layers, associated materials, and micro-features such as postholes or foundation trenches will be essential for distinguishing between deliberate ritual deposits and structural collapse. That level of stratigraphic detail is what separates a research excavation from a treasure hunt, and it is what will ultimately determine whether the finds can tell us something meaningful about how the Ho rulers used this space.
Open questions as fieldwork continues
Several significant gaps remain. No interim excavation reports, artifact inventories, or conservation assessments have been published as of this writing. The permit document establishes the legal framework and physical boundaries of the dig but does not describe what preliminary surveys, such as geophysical scanning or test trenching, may have revealed before full-scale work began.
“We are working trench by trench, following the stratigraphy as it presents itself,” said one member of the excavation team who spoke on condition of partial anonymity, noting that formal results would be released through the lead institution. “The gold-glazed fragments from earlier seasons told us something was here. Now we have the permit and the resources to find out how much.”
The full identity and institutional affiliation of the lead archaeologist are only partially legible in the published government decision, which references the surname Nguyen. Whether the excavation team includes international partners, university researchers, or conservation specialists from outside Vietnam has not been publicly disclosed. That lack of detail makes it difficult to anticipate what analytical techniques, such as residue analysis, 3D photogrammetry, or micro-stratigraphic sampling, might be applied to recovered artifacts.
There is also the question of what triggered this excavation now. The citadel has been a World Heritage Site since 2011, and the altar area has been known to contain significant subsurface remains for years. Whether the decision reflects new funding, a shift in heritage policy, or findings from recent preliminary surveys has not been explained in the public record.
What comes next at the Nam Giao altar
Vietnamese archaeological projects of this scale typically produce preliminary findings within the first months of active fieldwork, particularly when trenches are opened in sequence rather than all at once. The most reliable updates will come from interim reports published by the excavation team’s home institution or from the Ministry of Culture, Sports and Tourism. For now, the permit itself is the strongest piece of confirmed evidence: a clear signal that Vietnamese authorities are investing in systematic exploration of one of the country’s most enigmatic royal ceremonial spaces.
The gold-glazed dragons are real. They have been documented in earlier, smaller recoveries from the citadel. Whether the current excavation will pull more of them from the earth, and whether those finds will finally reveal how the Ho kings arranged their most sacred ritual ground, is a story still being written in the soil of Thanh Hoa province.
More from Morning Overview
*This article was researched with the help of AI, with human editors creating the final content.
