XI'AN, Jan. 12 (Xinhua) -- Three tombs believed to date back to the Tang Dynasty (618-907) have been discovered in Xi'an, the capital of northwest China's Shaanxi Province, local authorities said on Thursday.

The three tombs were unearthed in Chang'an District in Xi'an, according to the Shaanxi provincial institute of archaeology.

In one of the tombs, a well-preserved 1,769-word epigraph was found on a stone measuring 76.7 centimeters in length, 77.1 centimeters in width and 14.5 centimeters in height. It was written by Liu Gongquan, a famous litterateur and calligrapher during the Tang Dynasty.

The plane of the tomb where the epitaph was found is in the shape of a knife handle and is positioned in a south-north direction. One tower-shaped pot lid, two pottery busts and one pottery dog were also unearthed.

The epitaph was written by Liu in his later years. It has been excavated by archaeologists and will provide important physical materials for the study of Liu's calligraphy art, said Chen Xuwei, a research intern at the Shaanxi provincial institute of archaeology.