Archaeologists working in southwestern Mongolia say they may have discovered the remains of an 800-year-old fortress built for Genghis Khan, founder of the Mongol Empire.

A team of Japanese and Mongolian archaeologists began surveying the site, about 880 kilometres from the Mongolian capital of Ulan Bator, in 2001. They noticed that geographical features in the area were similar to landscape depicted in a travel book written by a medieval Chinese Taoism leader.

In 2004, the research team uncovered what they believe was Genghis Khan's palace. Now, they believe they may have found the remains of a fortress, surrounded by a soil wall measuring 200 metres by 200 metres.

On the site, the team has unearthed wood chips, ceramic pieces and animal bones. Carbon dating performed last summer determined the wood pieces were from the 12th to 13th century, while the bones were estimated to date to the 14th century.

The archaeologists believe the items were likely from a castle used as a military base when Genghis Khan was leading an invasion of central Asian countries. The fortress is said to have been commissioned by a close aide to Genghis Khan in 1212.

The research team told the Asahi Shimbun they hope the discovery will be useful in learning about the Mongol Empire’s western expansion strategy.

“We hope the discovery will be useful in ascertaining the history of the Mongolian Plateau between the thirteenth and fourteenth centuries,” team leader Koichi Matsuda of Osaka International University told the paper.

Genghis Khan died in 1227 while fighting in the region of Xixia. His burial site in the Mongolian Plateau was kept secret and remains unknown to this day.