The Chinese Academy of Social Sciences on Wednesday announced China's six top archaeological discoveries in 2009, including the discoveries of ruins of ancient paper-making workshops and the tomb of Chinese legendary general Cao Cao.

The front chamber of Cao Cao's mausoleum in Anyang county, Henan province.

The ruins, spanning from Song Dynasty (960-1279) to Ming Dynasty (1368-1644), were located in the city of Gao'an in eastern Jiangxi Province

The site covered a total area of 700 square meters and were fully unveiled by the province's archaeologists in December in 2009, said Xiao Fabiao, a research fellow at the Jiangxi Provincial Institute of Cultural Relics and Archaeology.

"The discovery is significant," said Su Rongyu, a researcher at the Institute for History of Natural Science under the Chinese Academy of Sciences. "Because few relics of paper-making workshops had been uncovered before."

He also said the workshop ruins, where workers used to make paper from bamboo, were the earliest ones found in the country.

Paper, along with gunpowder, compass and movable type system are widely regarded as the four great inventions of ancient China. Paper-making in China was dated back to 150 A.D..