Few artifacts from the Sogdians have been found, but those that have offer insights into their role in the ancient world

"Of all the more than 60 stone tablets unearthed in Luoyang and bearing the epitaph for their Sogdian owners, only one was discovered during official excavation," says Mao Yangguang, a professor of history at Luoyang Normal University.

For the past decade Mao has been reading between those inscribed lines, hoping to garner more clues about a people who once controlled a crucial part of international trade but have become mere footnotes of history.

"The tomb raiding once rampant in this part of the country has left little for us, but this particular one, which was intact upon its excavation by archaeologists, is of special importance," Mao says.

"This is because the tomb owner, a man named An Pu, was no ordinary trader like most of his contemporary Sogdians, but a general who once fought to defend the borders of the Tang Empire (619-907)."

An Pu's grandfather, who went by the name An Xili, was the tribal leader of a small Sogdian kingdom northwest of the Chinese empire, Mao says.

"Around 630 An Pu and his father, whose name we have no way of knowing, reneged on their nomadic overlord and submitted to Tang. Appearing in the pages of history as something of a war god, An Pu proved invincible on the battleground and was made a general by the Tang court."

The Sogdian general died in 664, aged 64, and was later inhumed with his wife, who outlived him by 40 years. The burial ground was constructed by An Jinzang, An Pu's son, who, instead of leading a horseback life of his own, became a court musician.

"Between them the three generations of Sogdians witnessed the height of Tang, to which their own lives provided the most titillating annotations," Mao says.

"The love-hate relationship they had with the Chinese empire was characterized by mutual courtship and the occasional pang."

In an article written for the catalogue of a Silk Road exhibition at the Henan Provincial Museum, Sun Ji, a Chinese historian, cited a Tang Dynasty travelogue in which the Sogdians were described as "shrewd, cunning and reckless".