The “Stupa”
Inside the temple and palace city, the so-called stupa rises from the interior of the palace wall, visible from afar and at around 13 meters the highest point in the city. Today, a wooden post is set into its top, to which colourful Buddhist prayer shawls are attached and which, as a place of religious worship, is watered with airag and decorated with small offerings.
What is a Stupa?
The term “stupa” refers to tower-like structures that are used as sacred buildings in Buddhism. These are usually massive buildings without an interior, windows or doors, with a purely symbolic function. The design is based on the cardinal points and follows a clear geometry with symmetrical shapes. Stupas spread from India to the East and Southeast Asian region as far as Afghanistan. Over the centuries, different variations of the design emerged, whose three main functions as reliquary shrine, memorial and votive offering still exist today.
The Excavation at the Stupa
In order to clarify questions about the construction method and function of the stupa in Karabalgasun, we began excavating the northern part of the building structure in 2019. It was still clearly recognizable that the building had been constructed from rammed earth, so there was hope of finding preserved remains of wall cladding in the area of the base of the building under the eroded soil. In the upper layers, large quantities of burnt clay bricks were found, which bore witness to the centuries-long decay of the large building. Below this layer of rubble, a few centimetres thick burnt horizon with a high concentration of charcoal was preserved, which is possibly due to the destruction of Karabalgasun.
Remains of a Blind Wall
After a two-year break due to the pandemic, the excavation was finally able to continue in 2022 and we were delighted when we came across the intact remains of the building’s blind wall right at the beginning, which was uncovered over a width of 8 m within three weeks. The wall, which has been preserved to a height of around 3 m, has a sloping profile and is made of two or three layers of bricks placed one behind the other, which are arranged smoothly and flush on the outside. In some openings of the wall, remains of the wooden beams and planks originally used there were preserved, from which samples were taken for archaeobotanical analyses and C14 examinations. As a binding agent, a layer of mortar up to 2 cm thick was inserted at irregular intervals every five brick layers from the nineteenth layer onwards. Between the remaining layers, only clay was used as a binder.
Other Buildings
In the excavation area in front of the wall, in addition to traces of the excavation pit, various features were found that point to another building on this site. Many remains of wood, charcoal and the aforementioned roof tiles suggest a roofed wooden structure that had been destroyed by fire. Among these were fragments of eaves tiles with Tang-period floral decoration, which have been found in all areas of the town site investigated to date.
While initial information on the construction of the stupa is now available, it is still unclear which religion it is associated with and how it was used. What is certain is that it was built at the same time as the city complex and is not a later addition. Further excavations in the area of the building may be able to answer unanswered questions.