A cosmopolitan capital

In the seventh and eighth centuries, the eastern end of the overland routes was Chang'an, the capital of the Tang dynasty (618 to 907), near modern Xi'an. With perhaps a million people inside and around its walls, it was among the largest cities on earth. Its streets formed a strict grid, and trade was confined to two great markets. Foreign merchants clustered in the Western Market, closer to the gates that led toward Central Asia, where Sogdians, Persians and Turks sold horses, gems, spices and wine.

Foreign fashion swept the city. Sogdian dancers performed a spinning dance that poets described in wonder; Central Asian musicians shaped court music; aristocrats, women included, played polo, a game that came from Iran. Pottery figures buried in Tang tombs show camels loaded with goods and grooms with beards and pointed hats, the stereotypical foreigners of the day. Tang culture did not merely tolerate the outside world; for a time it found it glamorous.

Rebellion and retreat

That openness had limits, and it suffered a heavy blow in 755. An Lushan, a frontier general of Sogdian and Turkic descent who had become a favorite at court, launched a rebellion that took years to crush and devastated northern China. Afterwards, suspicion of foreigners grew, and the court pulled troops back from the west to fight at home.

The vacuum was filled by others. The Tibetan Empire, then at the height of its power, seized the Hexi Corridor and ruled Dunhuang from 786 to 848, when a local leader, Zhang Yichao, drove the Tibetans out and offered allegiance to the Tang. Earlier, in 751, a Tang army had been defeated by Abbasid forces at the Talas River in Central Asia. Neither event closed the routes, but together they ended the period when one Chinese state dominated the eastern half of the network.

The caves of Dunhuang

Dunhuang's greatest legacy is the Mogao caves, a cliff riddled with about five hundred decorated chambers cut between the fourth and fourteenth centuries. Monks, merchants and officials paid for murals and statues as acts of devotion, so the caves record a thousand years of Buddhist art along with portraits of donors and scenes of daily life, including caravans and bandits.

One small chamber, now called the Library Cave, was packed with manuscripts and paintings and then sealed around the year 1000. No one knows exactly why. Perhaps monks feared invasion; perhaps they were storing worn out sacred texts that could not simply be thrown away. In 1900 a Daoist priest who had appointed himself caretaker of the site, Wang Yuanlu, found the sealed door behind a mural. Inside were tens of thousands of documents in Chinese, Tibetan, Sanskrit, Sogdian, Khotanese, Uyghur and even Hebrew: sutras, contracts, letters, school exercises, calendars and paintings.

Scattered treasures

News spread slowly, and the first outsider to exploit it was Aurel Stein, working for British India. In 1907 he persuaded Wang to sell him thousands of items for a modest sum, which Wang said he would spend restoring the temples. Stein could not read Chinese and relied on his secretary. The next year came the French scholar Paul Pelliot, who, unlike Stein, read Chinese fluently and chose the most valuable texts by working through the hoard by candlelight. Japanese, Russian and American expeditions followed, and Chinese officials carted the remainder to Beijing, losing many items to theft on the way.

Among Stein's purchases was a printed copy of the Diamond Sutra with a date corresponding to 868. It is the world's oldest dated printed book, and it is now in the British Library in London. To this day the Dunhuang documents are scattered among libraries in London, Paris, Beijing, St Petersburg, Tokyo and elsewhere. Since 1994 the International Dunhuang Project has worked to put the scattered manuscripts online, free to all, so that scholars can at least reunite them on screen.

Worked example: theft or rescue?

Was Stein a thief or a rescuer? Make the strongest case for each side. For theft: Stein knew the documents were precious, paid a small fraction of their value, took advantage of a poor caretaker and a weak government, and removed a nation's heritage to a foreign empire. Many Chinese scholars still describe the episode as a national humiliation, and a later American visitor peeled murals off the cave walls, which looks hard to defend by any standard.

For rescue: Wang Yuanlu had already been giving items away, the Qing government had shown little interest, and the documents taken to Beijing suffered heavy losses on the road. Items in London and Paris were catalogued, published and studied, which created the field of Dunhuang studies. The rescue argument has a weakness, though: it judges by outcomes Stein could not have known, and it assumes outsiders had the right to decide.

A fair conclusion separates questions. Was the purchase legal at the time? Probably, under the lax rules of 1907. Was it fair? Hard to argue so. What should happen now? Here digitization offers one answer that respects both scholarship and the claim that a people's past belongs, first, to them.