Archaeologists unearth details about glory of an ancient metropolis and strive to get a clearer idea of the colossal site's place in history, Wang Kaihao reports.

Editor's note: A national comprehensive research program, launched in 2002, to trace the origins of Chinese civilization, has led to the excavations and studies of key sites that are about 3,500 to 5,500 years old. It has revealed a host of secrets about ancient China, including how early civilizations were formed and how they merged to create unity in diversity. China Daily speaks to experts working at these sites to decode their recent discoveries.

Near the northern edge of the Loess Plateau on the west bank of the Yellow River, stands the Shimao site in Shenmu, Shaanxi province. History has played tricks, in the past, with its legacy and identity which is now being better appreciated.

It is located in an area where a group of Ming Dynasty (1368-1644) military structures remained along the Great Wall. This led to confusion. When people, in recent times, saw stone walls still standing meters high at the Shimao site, they sometimes confused them as a part of the Great Wall. However, documentation, actually written in the Ming Dynasty, said it was probably built during the Tang Dynasty (618-907).

They were all wrong. Shimao is actually millennia older. This is beyond dispute as it has been verified by archaeologists. The capital, presumably, of a regional power was absent in ancient text records, but many mysteries and surprises lurk under its colossal structure.

Covering 4 million square meters on a terrace, nearly six times the size of the Forbidden City in Beijing, the approximately 4,000-year-old Shimao site is the largest city ruins of its era in China. In the eyes of scholars, it is also probably among the biggest archaeological discoveries in recent decades and is closely connected to the birth of ancient Chinese civilization.

Sun Zhouyong, now head of Shaanxi Academy of Archaeology, has been devoted to the excavation and studies of Shimao over the past decade. Recalling his first impression of the "crazy stones", as he dubbed them half-jokingly, Sun says he was stunned, considering prehistoric cities in China were usually built up through the earth.

"The constructional components and walls were so well preserved," he says. "And stone statues were still there, in the magnificent 'palace' atop the terrace."

Its scale astounds all. The total length of the Shimao stone walls, at least 2.5 meters wide, exceeds 10 kilometers. The highest surviving section is 5 meters above the ground.

"To construct these walls, the human labor was much more than the number of people living in this settlement," Sun says.

The site was first found by archaeologists in the 1950s, and preliminary research began in 1976 when precious pieces of jade were recovered. Nevertheless, it was only when Sun led his colleagues in the first formal excavation, beginning 2011, that scholars began to realize that their previous understanding of the site was only the tip of the iceberg.

"The site is so huge, but the local landscape is rugged," Sun says. "We can hardly imagine the extent of the site when standing in it, but we can see relics from the period of Longshan Culture (2500 to 2000 BC) almost on every hill."

Sun and his colleagues are lucky. In spite of erosion over millennia, the general layout of the stone city and local landscape amazingly remain intact. Continuous field research helped people to piece the puzzle together and unveil the "epoch-making" discovery.

"Based on research of unearthed artifacts and funeral customs, we can see the city was built by native people who had lived in this place for a long time," Sun says. "As time passed by and society got increasingly complicated, such a core settlement of a prototyped state was formed in Shimao."

Shimao is not alone. Through their studies, archaeologists can now gradually "rebuild" that ancient state, which was presumably from 4,300 to 3,800 years ago. About 100 smaller city ruins were also found in the nearby areas, just like satellite settlements surrounding a metropolis.

In Sun's eyes, they represent a community and society with a pyramidal structure. "Before further evidence is found, it's better to call it the center of the regional regime controlling North China around 2000 BC."

Once Shimao city was excavated, some scholars tried to connect Sun's groundbreaking findings to existing documentation, and thus usher some legendary rulers like Huangdi ("Yellow Emperor") and Yao from suspected mythology to actual history. But Sun thought it is still too early to credit Shimao to any famed rulers recorded in early Chinese history.

"You can only talk based on the material you unearth," he says. "But when combining approaches of archaeology, natural sciences and ancient documentation, we can have new views on the relations between prehistoric civilizations and ancient legends."

Nonetheless, the city per se has already reshaped people's understanding of history, on architectural development in particular. For instance, the previously known earliest physical evidence of bastions-a structure projecting outward from the city wall-were from the Han Dynasty (206 BC to AD 220), and barbicans-the outer defense perimeter of a city-were believed to first appear in China in the Tang Dynasty.

Shimao has both, a few thousand years earlier than previously believed.

'Terrace of a royal city'

Since 2016, the site of the 80,000-square-meter Huangchengtai, or "the terrace of a royal city", has been the focal area of Sun's studies. The exquisitely designed gates and protective walls, as well as ruins of grand high-level architecture, showed its core role in Shimao.

About 40,000 relics made of jade, bronze, stone and bones, as well as pottery items, may compose a kaleidoscope for today's viewers to imagine the life of rulers in Shimao. Fragments of murals, pieces of silk and lacquerware are also enticing for researchers.

Discovery of the square architectural foundation, covering 16,000 square meters, is of the greatest significance on Huangchengtai. Though only the southern side of the foundation has been fully unveiled, as many as 70 stone reliefs of human faces, mythical animals or symbols were found.

"Currently, we're still unsure whether these statues were from a giant shrine and were moved to this foundation, which features 'a palatial city', after the original architecture got destroyed," Sun says. "It needs further study. But if so, it may reflect a huge social change among the upper class."

According to Sun, Huangchengtai is the best-preserved ruins of an early-stage palatial city in East Asia. But findings like the stone reliefs also vaguely portray a picture of a "holy city". As Sun adds, walls were built in Shimao not only for safety, they also stand for kingship and theocracy.

About 20 ceramic eagles and numerous bones used for oracles further indicate the exceptional status of Huangchengtai in a religious system. Separately, over 10,000 needles made of bones show that the site is an economic hub.

And the discovery of 20 mouth harps, the earliest known evidence in the world, from Huangchengtai also broadens people's knowledge of music. "The mouth harps also offer an important clue to study human migration and cultural exchange in early history," Sun says.

Put into a bigger picture of communications, Shimao looks like a seat of power with a wide influence. But many mysteries still remain.

More and more clues, including comparative studies of relics and DNA analysis, have shown the close links between Shimao and the roughly contemporaneous Taosi site in nearby Shanxi province. Were they allies or enemies?

Some ceremonial jade artifacts from Liangzhu Culture were found in the walls of Shimao. Centered in present-day Hangzhou, Zhejiang province, which is more than 1,600 kilometers away, Liangzhu Culture existed approximately 5,300 to 4,300 years ago. How communication spanned such long distances needs further research.

"The Shimao city ruins offer rich references for our studies on formation and development of early Chinese civilization," Sun says. "We can thus better understand its diverse origins."

In the ongoing national-level comprehensive research program to trace the origins of Chinese civilization, Shimao was listed as one of the core sites.

Wang Wei, a researcher at the Chinese Academy of Social Sciences' Academic Division of History and a leading expert of the program, believes studies on sites such as Shimao helped form a more scientific system to evaluate a civilization.

Among Western scholars, the appearance of metallurgy and written characters were long considered to be indispensable elements to define a civilization. "But the criteria are largely based on recent centuries' research on Mesopotamia and ancient Egyptian civilizations, and are not ubiquitous," he says.

In Wang's opinion, based on recent archaeological studies in China, key indicators defining a civilization can be wider. Social structures, for instance, would play a part with a clear-cut division of classes, usually marked by a ritual system.

"Apparently, the supersized Shimao ruins make the northern Shaanxi province a focal area to study how civilization developed," Wang says.

A worldwide significance

Shimao is not an unfamiliar name beyond China. As early as in the 1920s, many ceremonial jade pieces were discovered in the area, which were later believed to have come from the Shimao site. They fell into the hands of antique dealers and foreign "explorers", and are now scattered around the world.

Nevertheless, following work done by Sun's team, overseas scholars may be ushered to attach close attention to the location of those exquisite artifacts.

A highlighted moment came in 2020 when the "Neolithic City of Shimao" was listed among the world's top 10 archaeological findings of the past decade by the Archaeology journal, which was published by Archaeological Institute of America.

In February, a paper titled Shimao and the Rise of States in China: Archaeology, Historiography and Myth was published with US-based journal Current Anthropology and has been widely noticed in academia home and abroad.

Overseas authors of the paper critique the ongoing study methods on Shimao while highlighting the crucial role that the site played in the early stage of Chinese civilization. More importantly, eight renowned scholars around the globe, including Sun, commented on and replied to questions raised by the authors in the publishing.

"The authors may haven't fully understood the recent development of Chinese archaeology and thus nurtured some biased viewpoints," Zhang Meng, an associate researcher with Shanghai-based Fudan University, says. "But the paper as well as the comments showed how international and domestic scholars explained the history behind Shimao through multiple dimensions, and such exchanges can enrich our own researching methods."

Considering Shimao as a milestone marking the trajectory of urbanism, Sun also knows the significance of placing the site in a bigger picture, involving civilizations in Mesopotamia and the Indus Valley.

"We can see some similarities among the stone structures of these regions though there is no evidence to show contact," Sun says. "But it is undeniable that Shimao benefited from a wide network of intercultural communications.

"Shimao, owing to its unique geographic location, has an advantage to be compared with its contemporaneous counterparts across Eurasia," he says. "Seeing how they were formed and how they evolved, we can better reveal the contribution made by Chinese civilizations to the world."