The Starset SocietyA city larger than many in Europe at the time was perched in the mountains.
The history of the Silk Road, a vast network of ancient and medieval trade routes connecting Beijing and Hangzhou with Constantinople and Cairo, has mostly been focused on its endpoints: China and the West. Less was known about the people and cultures the traders encountered along the way. Given the length of the route, there must have been a lot of encounters. Traders passed through large cities like Tehran or Baghdad, which we know very well because they still stand today. They also crossed the Tien Shan, the largest east-west mountain range on the planet.
“People thought these mountains were just places the caravans had to cross and get through but not really a major contributor to commerce themselves,” says Michael Frachetti, an anthropologist at Washington University in St. Louis, who led a team that used drone-based lidar to map two mountainous cities at the western end of Tien Shan in the modern-day Uzbekistan. Both were built over 2,000 meters above sea level like Machu Picchu or Lhasa, Tibet. One of them, the Tugunbulak, was larger than Siena, one of the most influential city-states in medieval Italy.
Into the mountains
“The Silk Road was a complicated complex representing in some cases actual pathways the caravans could traverse, but also general exchange between East Asia and Europe. If you ask me, as an archeologist, the foundations of Silk Road can be traced back to the Bronze Age. But the peak of this exchange we date to the medieval period, between the 6th century and the 11th century,” says Frachetti.
When you were a medieval merchant leading a caravan carrying silk, perfumes, mirrors, and other goods you just bought in China, you had roughly a one-year-long journey ahead of you before you could sell them in Europe. The first really tough part of this journey was crossing the Tien Shan range using the mountain paths that avoided the Taklamakan Desert.
“Those mountains have been seen as peripheral, merely a barrier to movement and to trade,” Frachetti said. Trade mostly occurs in cities, and cities built in mountains are relatively rare. But that doesn’t mean they don’t exist. “A lot of our work in the last 20 years has been focused on looking at the mountains not only as the barrier to movement and source of materials, but as a source of social engagement,” Frachetti says. And this work eventually led to the discovery of Tashbulak, a medium-size settlement with an area of around 25 hectares (61 acres). It sits at the western end of the Tien Shan range, around 6,500 feet above sea level in modern-day Uzbekistan.
Tashbulak had a citadel in the center and dense urban architecture with 98 buildings enclosed by city walls. Its size and layout are similar to other towns from that era in that region.
A buried metropolis
While inspecting pieces of pottery found in the Tashbulak site in 2015, Frachetti met a local forest inspector who claimed he saw similar pottery in the backyard around his home. Frachetti paid the inspector a visit and discovered the inspector’s home was built on top of another medieval citadel. A few years later, in 2022, Frachetti’s team was ready to map this new, potentially interesting area with the latest piece of tech in archeology: the lidar drone.
“The area is a high-altitude plateau; it’s very rugged,” Frachetti says. This didn’t bode well for discovering medieval cities, but the upside was there was no tree cover—drone flybys could be done at low altitudes, which increases the mapping precision. After multiple sorties with the drone, Frachetti’s team pieced together a point cloud map of the entire area and ran an AI algorithm to extract features that could point to human-made structures. “Without really understanding what you’re looking at, [things] can be easily taken for natural terrain,” Frachetti says. But when the AI finished its job, the hills revealed their staggering secret.
The city of Tugunbulak, which stretched beyond the forest inspector’s house, had powerful walls enclosing the area of 120 hectares, nearly five times larger than the Tashbulak site. With those walls, there was a dense architecture with hundreds of buildings, streets, palaces, plazas—even industrial facilities the Frachetti’s team suspects were used to produce iron or steel.
To put that in perspective, the medieval walls of Siena, one of the foremost cities in Italy during that time, surrounded an area of 105 hectares at the peak of its power. Genoa, another crown jewel among Italian medieval cities, between the 6th and 11th centuries, had walls protecting just 20 hectares, an area bumped up to around 50 hectares by the time of Frederic Barbarossa’s invasion between 1155 and 1158 CE.
Tugunbulak was a monster of a city. But what did it look like?
A city of iron?
“If you looked at Tugunbulak from the outside you would have seen these kind of rocky walls. They appear to have been made in a technology called rammed earth. The builders would take mud and press it into something almost like cement—a very high labor, very dense, very defensive and fortified material,” Frachetti says. Rammed earth was a dominant building technique used in the early stages of Tugunbulak’s development. “The later phase in the site, we see some stone architecture foundations with mud brick on the top. They used local resources and building techniques that were popular in the region,” Frachetti explains.
According to the team, the main contribution of the city to the Silk Road trade was iron, as the surrounding mountains are particularly rich in iron ore. One of the still unanswered questions was about the way Tugunbulak’s people lived and worked. Were they skillful blacksmiths forging iron and perhaps even steel in their mountainous city? Did at least some of its inhabitants live the lives of nomads, visiting the city only periodically to trade on market days or did they live there permanently? “We’d like to know how extensive was the industry there—what level of production were they actually doing?” Franchetti says. He suggested that a shifting, seasonal population that most likely lived in yurts spread outside of the walls was more likely in the smaller Tashbulak, considering it lacked residential suburbs. “Tugunbulak must have been a far more organized political entity. Their power and their influence must have been significant in the broader economy of the Silk Road,” Frachetti claims.
But it’s going to take a long time before we know anything for sure. Lidar drone mapping saved Frachetti’s team roughly a decade; otherwise, they would have needed to map an archeological site of this size using traditional methods. What’s ahead now is the meticulous and slow work on the ground. “We’re on full excavation program; we began excavating the site in more extensive detail,” Frachetti says. “And we’ll be continuing that work for the next decade, if not more. It gives us a lifetime of activity,” he adds.
Read more at arstechnica.com
