A part of the epitaph unearthed in one of the three tombs. [Photo provided by Shaanxi Provincial Bureau of Cultural Relics]

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 epitaph was found on a stone measuring 76.7 centimeters in length, 77.1 cm in width and 14.5 cm in height. It was written by Liu Gongquan, a famous litterateur and calligrapher during the Tang Dynasty.

The tomb where the epitaph was found was built 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, says Chen Xuwei, a research intern at the Shaanxi provincial institute of archaeology.