On a small island in the center of the remote lake of Tere-Khol, at the foot of the mountains of southern Siberia, near the border with Mongolia, are the ruins of Por-Bazhyn (also called Por Bajin), a structure which at first glance looks like a fortress. Por-Bazhyn, which means “clay house” in the Tuvan language, and has been known since the 18th century, but was not explored until the end of the 19th century. Since then, the complex has been the subject of fascinating and frustrating theories in equal measure, as experts are unable to know who built it or why.
Por-Bazhyn was first explored in 1891 by a Russian archaeologist who realized the similarity between the layout of Por-Bazhyn with Kara-Balgasun, the former capital of the Uyghur empire in the 8th century. On the basis of this finding, the monument was dated to that time. It was also the first hypothesis, which gave rise to the name “fortress”.
The first excavations at this site were not carried out until almost 60 years later by another Russian archaeologist who saw construction features typical of Chinese Tang dynasty architecture. On the basis of anecdotal evidence, the so-called Selenginsk inscription, the lead archaeologist of the excavation, SI Vainshtein, claimed that Por-Bazhyn was a defensive fortress built by the second Uyghur ruler, Boyan-Chur, in 750 AD. Vainshtein’s hypothesis soon became the most accepted and disseminated by other researchers, despite the fact that it was based solely on speculation.
In 2007, a large-scale fieldwork was carried out by the Russian Academy of Sciences, the State Oriental Museum, and the Moscow State University. The archaeologists found clay tablets of human feet, drawings of faded colors in the plaster of the walls, giant doors and fragments of burned wood, but nothing substantial that could provide a definitive answer as to why the structure was built.
Another mystery is the absence of traces of dwellings. Through radiocarbon dating, it is suggested that the fortress was built between 770 and 790 AD, some 20-30 years later than previously believed.. Since Boyan-Chur died in 759 AD, it was hypothesized that his son Byogyu-Kagan built the place. Byogyu-Kagan was known to have declared Manichaeism the state religion, and may have commissioned Por-Bazhyn as a Manichaeism monastery, which would explain his isolation. However, Byogyu-Kagan died in 779, during an anti-Manichean revolt, which would explain why there are no traces of dwellings, since the monastery would never be completed. Of course, there is also no evidence to support these interpretations.
Now the future of the Por-Bazhyn is up in the air. The structure is located in an area where the water level rises incessantly. According to one of the researchers, in 80 years the structure could be completely gone under the lake. There is also evidence of damage from at least two earthquakes in the past. One of them may have occurred during construction in the 8th century, and another, catastrophic, after the island was abandoned.