Japanese researchers who made the first comprehensive study in six decades of a crumbling brick tower from an 11th-century fortress town in eastern Mongolia say their findings shed light on the little-known nomadic Khitan people.

The tower is the centerpiece of ruins in Kherlen Bars, a settlement that dates to the Liao Dynasty (916-1125), when the Khitan flourished. The site is about 600 kilometers east of Ulan Bator, Mongolia's capital.

A team of researchers from Nara University made a number of discoveries about the structure of the tower. They also found remnants of a mural that suggests the Khitan were more advanced than historians realized.

The research team was headed by Tetsuo Shoji, an associate professor of information media, and Yoshihiro Senda, a professor of archaeology whose expertise is castles.

The team, working with the Mongolian Academy of Sciences' Institute of Archaeology, took 3-D laser measurements of the ruins in June.

The eight-sided tower is thought to have been constructed around the 11th century. The bricks are stacked high in circular formation to create a hollow chamber inside. Broken pieces of timber are still visible in the inner walls, suggesting the tower had seven levels. The top of the tower collapsed long ago, so the structure now rises to a height of only 16.5 meters.

With brick walls 1.8 meters thick, the structure has a diameter of 9 meters. The diameter of the inner chamber is 5.6 meters at the base and narrows in height. The researchers confirmed the presence of plaster on a part of the inner wall and traces of color, indicating a mural once covered the surface.

According to Takashi Matsukawa, a professor of Mongolian history at Otani University who visited the site in May, many Liao Dynasty towers exist in present-day China's Inner Mongolia Autonomous Region, then the Khitan kingdom's base. But the Kherlen Bars tower is the only one known to exist within the borders of modern Mongolia.

It sits on what was the front line of the Liao's entry into the Mongolian steppes. The ruins are thought to have been a military garrison where soldiers would gather to shore up the kingdom's northern defenses.

Mongolian scholars excavated the area around the tower in 1953, but no full-scale investigation had been conducted since.

"Precisely recording the pagoda's measurements is a highly significant accomplishment," said Matsukawa.

Source: The Asahi Shimbun