Fortifications older than the Great Wall of China discovered in Chinese mountain pass

Archaeologists in China have discovered a 2,800-year-old fortified wall that predates the country's first emperor.

The wall, which runs through a narrow mountain pass in the eastern province of Shandong, was first constructed in around 800 B.C. At that time, it was about 33 feet (10 meters) wide. But it was expanded during the Warring States period (circa 475 to 221 B.C.) to be about 100 feet (30 m) wide, the Chinese news outlet Global Times reported.

The archaeologists also found the remains of houses, roads and trenches nearby. The team discovered the wall's age by radiocarbon-dating animal bones and plant remains from the same layer.

The Global Times, among others, said that this pushes back the construction of the Great Wall of China back by 300 years. However, experts that Live Science contacted disputed this. (Live Science reached out to the Global Times for comment, but it did not respond by the time of publication.)

This newly found wall "is, of course, not 'the Great Wall of China,'" Gideon Shelach-Lavi, a professor of Asian Studies at the Hebrew University of Jerusalem, told Live Science in an email. The newfound wall was built at a time when China was divided into a number of different states that were often at war with each other. Shelach Lavi noted that the different states often constructed walls during these conflicts.

One of these walls is called the "Great Wall of Qi," also known as the "Long Wall of Qi," which runs east-west through Shandong province, roughly from Pingyin county to the Pacific Ocean. The exact length of the wall is unclear, but it would have been more than 200 miles (322 km).

Related: Ancient Chinese burials with swords and chariot cast light on violent 'Warring States' period

But the newfound fortification is not part of the Great Wall of Qi, either, as that was built later, in around 441 B.C., Yuri Pines, a professor of Asian Studies at the Hebrew University of Jerusalem, told Live Science.

Pines called the newly unearthed wall a "very important" discovery and noted that it is at a narrow mountain pass that could have been used to invade the state of Qi. The new find suggests that there was a permanent garrison at the pass, likely made up of Qi soldiers, and that they built a narrow wall to try to block the pass.

"That the garrison tried to wall the narrow pass northward is indeed very interesting," Pines said. "But this is not a Long Wall, surely nothing on a par with the subsequent effort." While the newly discovered wall fortified a single narrow mountain pass, the Long Wall of Qi ran for more than 200 miles.

Live Science contacted archaeologists who discovered the 2,800-year-old wall remains but has not heard back at time of publication.

Great walls

The Great Wall of Qi was built by Qi, a state that was based in northern China, Pines wrote in a 2018 paper published in the Journal of the American Oriental Society. The wall protected Qi from invasions by other states south of the wall. While its exact route is unclear it ran east-west through Shandong province.

Construction of the Great Wall of China started during the reign of the first emperor of China, Qin Shi Huang, who ruled from around 221 to 210 B.C. The wall was later modified and renovated during the Ming dynasty (1368 to 1644) UNESCO reports. It was built to protect China from nomadic groups that lived north of China.

When he started construction of the Great Wall, the first emperor made use of earlier walls built by the different states — including the Great Wall of Qi — and connected parts of them together to help build the Great Wall of China, UNESCO notes.