Three relics experts from Northwest China's Shaanxi province flew to the United States on Friday where they will painstakingly repair two stone horses of the Tang Dynasty (AD 618-907).

Both stone horses are kept in the University of Pennsylvania's museum in the US.

"Our work is to repair the stone relics, which were broken into pieces in the course of being smuggled abroad," Zhou Ping, one of the relics-repair experts from the Xi'an Heritage Restoration Center, told China Daily in a telephone interview before boarding the airplane in Shanghai on Friday.

The two other relics-repair experts to join in the four-week mission are Yang Wenzong from the Shaanxi History Museum and Liu Xilin from Xi'an Heritage Restoration Center.

The two stone horses were part of a group relief sculpture in the cemetery of Li Shimin, the second emperor of the Tang Dynasty, who died in AD 649 and was buried in the mausoleum of Zhaoling located in Liquan county, Shaanxi province.

"The world-famous six Zhaoling Bas-relief Stone Horses were created to remember the great achievements of the emperor. The six steeds were with Li Shimin as he fought and won decisive victories in the unification of the Tang Dynasty," said Zhou Kuiying, director of the relics protection division of Shaanxi provincial heritage administration bureau.

The six stone horses, in relief sculpture, were carved with skilled techniques. In simple styles, all look strong and vigorous in various postures.

Two of the great works were stolen and shipped abroad in 1918 and are kept now at the museum in Philadelphia. The other four were moved to Xi'an Beilin Museum for better protection.

In March 2009, museum officials at the University of Pennsylvania decided to repair the two stone horse sculptures with an investment of $70,000.

They asked the Tang Daming Palace Foundation in Shaanxi province to send cultural relics-repair experts for the work in the museum, according to Sun Fuxi, deputy secretary-general of the foundation.

"It is the first time that Chinese cultural relics repair experts will work on Chinese cultural relics kept in a foreign country. We will have a close consultation with the museum for the return of the two horses for display in Xi'an," Sun said.

"We will try hard to promote the reunion of the six stone horses in Xi'an in October," Sun said.

By Ma Lie