The worship of Guanyin began around the third century, and the earliest Guanyin figure still in existence, believed to have been sculpted between the third and fourth centuries, is now at the Bingling Temple in Gansu.

"Any museum would be proud to own a wooden Song Buddhist sculpture, given the rarity of its kind," Tong says.

The Guanyin figure, which was bought back to China from a private collector abroad in 2005, reflects the reverence for Avalokitesvara after the religion started to spread in China.

The bodhisattva figure, who has male features in Indian Buddhism, gradually took on more female characteristics in China, and in the Song era, the icon was finalized as a female figure: the beard had been replaced by feminine decorative details. And in addition to an association with infinite compassion, the goddess embodied more blessings among a wide population of believers, such as a wish for children.