Ma said that the discovery of the graves of Liu Heng's empress and his mother further indicated that the grand tomb in the center should be the emperor's long resting place.

"It is the earliest Western Han royal graveyard in which the emperor's tomb was put in the center and was surrounded by burial pits," he said.

The discovery of Baling also means that the whereabouts of all 11 Western Han emperors' mausoleums in or near Xi'an, then the national capital known as Chang'an, have been confirmed, Ma said.

The grand tomb was a milestone in the evolution of Chinese royal mausoleums, said Liu Qingzhu, an archaeology researcher with the Chinese Academy of Social Sciences.

The emphasis of previous rulers' mausoleums was more on connections within their own families. For example, royal couples were often buried together.

"But Liu Heng's tomb reflected that the country, represented by the emperor's power, was the priority," he said, adding that studies of the tomb also are a key to understanding the forming of China's national identity.