New discoveries at Liulihe provide fresh clues about the origin of the city that eventually became China's capital, Wang Kaihao reports.

Just over 3,000 years ago, the newly established Western Zhou Dynasty (c. 11th century-771 BC) included present-day Beijing area under the rule of a united central kingship for the first time.

After the fierce war that ended the Shang Dynasty (c. 16th century-11th century BC), the Zhou king introduced enfeoffment system, under which land was given to the leaders of vassal states in exchange for their loyalty, to pacify people and govern the vast territory. The Yan state, whose leaders were from the same clan as the Zhou kings, rose around Beijing, marking the birth of the city.

Thanks to the Liulihe Site, which covers 5.25 square kilometers in the Fangshan district on the southwestern outskirts of the capital, more is left of that prosperous era than historical documents.

READ MORE: DNA helps uncover ancient ordinary families linked through marriage

Since it was found in 1945, Liulihe has continued to yield evidence of history. In the 1970s, for example, the milestone discovery of bronze wares inscribed with the name of the Duke of Yan finally confirmed it as the location of the seat of the vassal state. Now, an ongoing round of excavation that began in 2021 has revealed more about this ancient buried city.

As previous excavations located the city walls, some scholars had speculated that they were the boundary of an inner city, and that an outer city should also exist. This theory has been confirmed by the new findings.

According to Wang Jing, the lead archaeologist from the Beijing Institute of Archaeology, recent excavations confirmed the existence of a second layer of city walls and moats.

The outer city wall is located about 350 meters north of the previous northern boundary, and is between 6 and 9 meters in width. The moat is between 3 and 5 meters from the wall, with an average width of 7 to 8 meters. Though many parts of the moat have been eroded by a nearby river, the surviving 1,020-meter section has already amazed archaeologists.

"Based on the position of the outer moat, it is estimated that the city could reach a square kilometer in size," Wang says. "It surpasses our current understanding of the complexity of Western Zhou cities."

New knowledge has also come from the inner city, which it is estimated covers 600,000 square meters. Recent discoveries include large-scale rammed earth building foundations spread across 2,300 sq m, and which is larger than similar findings in China from the time, as well as wells, some of which are over 10 meters deep.

"They may provide clues to the different urban functional zones of the city," Wang explains.

The 82-degree orientation of both the inner and outer cities also turns out to be identical to the newly excavated city ruins of Zhouyuan Site in Shaanxi province, capital of the Zhou Dynasty (c. 11th century-256 BC).

"They are the only two known city ruins from the Western Zhou period with multiple layers of city walls," Lei Xingshan, an archaeology professor at Beijing Union University, says. "The identical orientation and complicated structure indicate the existence of a rigid ritual system."

Echoing recordings

According to ancient recordings, Lord Shao, a member of Zhou royal family with the official title of Taibao was entrusted with founding the Yan state. In 2021, the discovery at Liulihe of inscribed ritual bronze ware in a nobleman's tomb, coded M1902, vividly brought that history back to life.

The simple phrase taibao yong yan ("Taibao built the city of Yan") directly connected this archaeological site to the key chapter of history for the first time. Other inscriptions also mentioned Lord Shao organizing a sacrifice at the palace of the Duke of Yan as a groundbreaking ceremony.

"This monumental finding of these inscriptions also indicates that a palace city could already have existed when Lord Shao came," Wang says. "He might have built a new city, probably the outer city we recently excavated."

Some histories are written, while others are hidden in the earth. Following the clues, Wang's team is still working to look for the palace. Their mission is to put together the pieces and work up an overview of the era.

During the current round of excavations, 17 tombs with burial passages, including M1902, indicating that their inhabitants were either of the ruling dukes' family or aristocrats, were found at Liulihe.

Wang says that DNA analysis has identified four generations of Yan dukes. As there is no mention of Yan lineage after Lord Shao in surviving documents until nine generations later, she says it is a key reference in filling in the gaps of history.

In-depth research of individual samples could also help to reveal a bigger picture, according to Wang.

Wu Xiaohong, director of the Commission of Archaeological Chronology of the Chinese Society of Archaeology, and her team have been unraveling the puzzles surrounding the man who had long been sleeping in M1902. According to bronze inscriptions, the remains are those of a historian named Huan.

Based on 60 samples collected from 40 spots around the tomb, radiocarbon dating is providing a picture of Huan's life.

"He was 40 to 45 years old when he died, probably some time between 1045 and 1010 BC," Wu says. "It not only unrolls the time of the beginning of Beijing, but also helps solve the chronological issue of the Western Zhou as a whole."

Due to the lack of an accurate timeline, opinion about when the Western Zhou Dynasty was established has varied, with 1046 BC being the most widely accepted answer based on the study of documents, archaeological and astronomical evidence.

"Huan witnessed the groundbreaking ceremony shortly after the Western Zhou Dynasty was founded, and the carbon dating results could provide supporting evidence," Wu adds.

Decoding lives

History is not only about kings and nobles. The job of archaeologists is also to shed light on the ordinary lives that may be absent in historical records.

A graveyard of 33 small-scale tombs for commoners dating to the middle of the Western Zhou Dynasty was found north of the city. Ning Chao, a researcher at Peking University, and his team are conducting DNA analysis of the bones.

Those buried there belonged to two families related by marriage, and the cemetery contains the remains of at least four generations. Consanguineous marriage between cousins has been proven through the samples.

"We were able to draw a family tree through the studies," Ning says. "It vividly explains how clans were organized at the time."

Lab research has also provided clues to diet and livelihoods. Plant remains found at Liulihe mainly consist of millet and sorghum, supplemented by soybeans and red beans with occasional traces of wheat.

ALSO READ: A plain that echoes with legends

"The agricultural structure reflects the typical dryland farming practices of northern China," Wang says.

According to animal archaeology studies, the diet of ancient inhabitants mainly consisted of meats like pork, beef and lamb, with fish and shellfish also consumed.

"Findings provided valuable information on the dietary differences among different social classes, as well, such as the population of migrants during the early Western Zhou period," Wang says.

After the Shang Dynasty was toppled, its descendants continued to live under their former adversaries. Studies indicate that some even emigrated to settle in the Yan state.

"Research method at the Liulihe Site could set an example for the adoption of new technology in the study of large-scale archaeological sites," Lei says. "It creates a paradigm for future work."

Contact the writer at wangkaihao@chinadaily.com.cn