One particularly vivid rendering can be found in a glazed ceramic camel unearthed in a suburb of Xi'an, capital in both the Han and Tang dynasties. Craning its neck upward, the animal seems to be grunting loudly. Whether it is because of the heavy load and a crushing sense of tiredness or the glimpse of an oasis or something else will forever remain a mystery.

Ge Chengyong, a Silk Road research expert who acted as a consultant for a previous exhibition in Hong Kong, where the camel was on view, says that "a lot could be deciphered by simply looking into what is between a camel's double humps", pointing to another ceramic rendition of the animal from a slightly earlier time.

Straddling its back are a pair of sacks decorated with a drunk propped against another man and a woman.

"The drunk with a thick beard and potbelly is Dionysus, the Grecian wine god who could bring people harvest - think grape harvest in particular - and good fortune," Ge says. "Those on his left and right are two of his disciples, Satyrs and Stola. The images are telltale signs of a grape wine culture that originated in the Mediterranean and kept the Chinese intoxicated - literally and metaphorically - throughout the seventh and eighth centuries."

It was even blamed for preventing Tang from staying sober, when the powerful and prosperous empire, convulsed by sudden rebellion that erupted in 755, plunged headlong into a downward spiral from which it never quite recovered.