Photos of the two horse relief scupltures at Penn Museum. [Screenshot Photo/Penn Museum website]

A Chinese museum in Northwest China's Shaanxi province has openly demanded the return of two horse relief sculptures displayed at a University of Pennsylvania museum. The sculptures were illegally sold overseas.

The Zhaoling Museum made its announcement on Jan 11 via its official WeChat public account, calling on the University of Pennsylvania Museum of Archaeology and Anthropology (Penn Museum) to return the pieces so that the "Zhaoling Liujun", a set of six horse relief sculptures, can be reunited.

The six memorialized horses lived during the Tang Dynasty. They were allegedly the favorites of Emperor Taizong, Li Shimin. Together with other decorations and monuments, the six pieces were supposedly placed at the gate of the emperor's tomb.

"We believe it is most reasonable for the two horses to be returned to China from the Penn Museum … The University of Pennsylvania has long been dedicated to global cultural heritage protection. We hope that the Penn Museum can reach a consensus with China on this issue and make a greater contribution to the protection of the common cultural heritage of human beings," the Zhaoling Museum stated.