"But it is clear that the tomb was built with imperial solemnity and scale, the 40-m tunnel leading to the tomb's gate being one example," Hao said.

It is also clear that the tomb was built and furnished austerely, which is in accordance with historical records saying Cao ordered his tomb to be built "on non-arable highland, with no (pyramid-shape) mound or any plantation upon it", and "no treasures of gold and jade in it", Hao added.

The fact that the tomb's location is only a few kilometers from Yecheng (to the southwest of today's Linzhang county, Hebei province), historically the political center of Wei kingdom, is also strong proof that it is Cao's tomb, according to archaeologist Liu Qingzhu of the Chinese Academy of Social Sciences.

In Yecheng, Cao built the famous Bronze Sparrow Terrace, where musicians and dancers would perform to entertain guests at his banquets.

Before his death, Cao left word he wanted his tomb to be built in a place where his children could see from the terrace anytime they remember him, or from where he, as a spirit in the underworld, could enjoy the performances on the terrace.

"The stone tablets bearing inscriptions of Cao's posthumous reference are the strongest evidence," said Liu. "No one would or could have so many relics inscribed with Cao' posthumous reference in the tomb unless it was Cao's."

Experts agree that excavation of the mausoleum has just started and further research and study would prove the historical importance of the discovery, considering the important role Cao played in history.

"The tomb is a capsule of the historical time in which Cao lived," said Liu. "For example, it will serve as a clear chronological reference for many other relics, whose age would otherwise be too difficult to tell."

As a king's mausoleum is often built in the center of a tomb compound, it is likely that there are many burial sites in the surrounding area, Liu added.