Silk princess painting

The Silk Road and Beyond (400 - 700 AD)

Silk princess painting (made eighth century AD), from Chinese central Asia

Once upon a time, in the high and far off days of long ago, there was a beautiful princess who lived in the land of silk. One day her father, the emperor, told her she must marry the king of the distant land of jade. The jade king could not make silk, because the emperor had kept the secret to himself. And so the princess decided that she would bring the gift of silk to her new people. She thought of a trick, she hid everything that was needed - the silk worms, the mulberry seeds, everything - in her royal headdress. She knew that her father's guards would not dare to search her as she left for her new home. And that, my Best Beloved, is the story of how Khotan got its silk.

The tale I have just told you - a 'Just So' story of one of the greatest technology thefts of history - is one that is presented to us in paint on a plank of wood that's around 1,400 years old. It's known as the 'Legend of the Silk Princess' and it is now in the British Museum. But it was found in a long-deserted city on the fabled Silk Road.

"I think the Silk Road, in terms of the movement of goods and ideas, is the 'internet of antiquity'." (Yo Yo Ma)

"... because it wasn't just silk that travelled, and frankincense, and rhinoceros horn, and all these wonderful products which we associate with it, but a much more humble but continuous trade - of people locally, trading to people with rather different needs and situations." (Colin Thubron)

I am listening to the noise of the people and the goods of the whole world on the move, passing through Heathrow Airport... we all spend part of our lives now on highways or airways - some real, some virtual - and as well as travelling them ourselves, we know that they fuel not just the economy but our imagination. In this, surprisingly little has changed since the eighth century. In the world we've been looking at this week, a world of enormous movement of people and of goods, one of the busiest highways of all, then as now, ran from China: the Silk Road - not in fact one single road, but a network of routes that spanned 4,000 miles (6,500 km) and effectively linked the Pacific to the Mediterranean. The goods on that highway were rare and exotic - gold, precious stones, spices, silk. And with the goods came stories, ideas, beliefs, and - key to our story today - technologies.

In this programme we're in the oasis kingdom of Khotan in Central Asia, which is where our painting was found. Khotan is now in western China, but it was then a separate kingdom and the beating heart of the Silk Road, vital for water and refreshment, and a major manufacturer of silk. Khotanese story-tellers created a legend to explain how the secrets of silk production - for thousands of years a Chinese monopoly - had came to Khotan. The result was the story of the silk princess, as told in our painting.

The picture is on a wooden board, and it was found in a small abandoned Buddhist shrine in Khotan. The shrine was just one in a small city of shrines and monasteries which had vanished beneath the sand for over a thousand years. They were rediscovered in about 1900 by the brilliant polymath Sir Aurel Stein, one of the pioneering archaeologists of the Silk Road, and it was Stein who revealed Khotan's importance as a pivotal trading and cultural centre.

I am sitting with the painting now. It's painted on a rough plank that is almost exactly the size of a computer keyboard - and the figures are quite simply drawn in black and white, with here and there touches of red and blue. It's pretty unprepossessing as a work of art, but then it was never intended to be a work of art, because this painting was made entirely to help a story-teller tell their story. Right in the middle is the silk princess herself, with her large and prominent headdress. And to make absolutely sure that we don't miss it, and that we don't fail to recognise that this is the focal point of the story, on the left a servant woman is melodramatically pointing at the headdress. The story-teller would then have told us that inside it there is everything you need to produce silk: worms of the silk moth, and the silk cocoons that they produce, and mulberry seeds - because mulberry leaves are what silk worms need to eat. Then we see what happens next. In front of the princess, the silk cocoons are piled up in a basket, and on the far right there is a man hard at work weaving the silk threads into cloth. So, the princess has obviously arrived safely in Khotan, and her trick has worked. This story, simply set out in three scenes, is a key document of what was in fact a transforming shift of knowledge and skill from the east to the west.

We've known for a long time that the Silk Road was vitally important in the developing world of the eighth century, but it is only relatively recently that it has secured its romantic reputation, as the travel-writer and novelist Colin Thubron knows well:

"The place of the Silk Road in history - it's almost impossible to exaggerate its importance, I think, in the movement of peoples, the movement of goods, the transport of inventions in particular, and ideas - and of course in the movement of religions. Whether it's Buddhism north from India and eastward into China, or the advance of Islam deep into Asia, all this is a Silk Road phenomenon.

"The term 'Silk Road' was coined by a German geographer called Ferdinand von Richthoven as late as 1887. It was never called the Silk Road before then, and then of course that fed into it all the romance of silk itself, its beauty, its luxury.

"I think the place of the Silk Road in the western imagination, the romance that it has, is actually quite a recent thing. Obviously certain products on the Silk Road gathered a kind of mystique, particularly when they came from a long way away. Not just a great cost, but also a strangeness, because people perhaps did not know the civilisations that had produced them."

As Colin Thubron implies, mysteries often generate stories to explain them, and since silk was by far the most important product travelling along this route, it inevitably inspired - in fact it needed - its own myth. Luxurious, beautiful and enduring, silk is almost synonymous with the land that first produced it over four thousand years ago and monopolised it for so long - ancient China. Long before the Roman Empire appeared, silk was already cultivated in China and exported on an industrial scale. The mysteries of its production were a highly protected secret; but secrets as profitable as this one never last, and Khotan was one of the beneficiaries.

Coming back to our painted plank, we can see that there is a fourth figure in the story - it's a man with four arms holding a silk weaver's comb and a shuttle. He is the god of silk, who presides over the whole scene, and gives spiritual sanction, ensuring that we see the princess not as an industrial thief but as a brave benefactress. And so the fairy-tale takes on the status of myth. The silk princess may not be quite on a par with Prometheus stealing fire from the gods, but she is firmly in the tradition of great mythological gift-givers, bringing knowledge and skill to a particular people.

The written versions of our painted story tell us what happened next. The princess gave thanks to the gods, and ensured that Khotan would keep the secrets of silk forever:

"Then she founded this monastery, on the spot where the first silkworms were bred; and there are about here many old mulberry tree trunks, that they say are the remains of the trees first planted. From old time till now, this kingdom has possessed silkworms, which nobody is allowed to kill." And silk production is still a major industry in Khotan, employing more than a thousand workers and producing around 150 million metres of silk a year as cloth, clothes and carpets. Of course, we've actually got no idea how silk in fact came to Khotan, but we do know that ideas, stories, gods and silk all moved along the Silk Road in both directions. The cellist and composer Yo-Yo Ma has long been involved in Silk Road studies, looking at how, through the centuries, ideas of all sorts, and particularly music, have moved between the Pacific and the Mediterranean:

"I think, over the years, members of the Silken Ensemble have been all over - from Egypt to Israel, to India, to Kyrgyzstan, to China, to Korea, but there is so much to learn. What we are trying to do is constantly learn. Old traditions, we don't want them to get lost, but we need to put them in a contemporary form. Being a musician, I was particularly interested in how music may have travelled. We have recordings only from about a hundred years ago, and so to look at that you have to look at the oral traditions, and to look at other kinds of iconography, such as, you know, what's in museums, what people wrote about - stories - and to be able to get a picture of how things were traded back and forth, both in the idea realm as well as material objects.

"The Silk Road is a metaphor for looking at anything that has moved through time and geography. A lot of people talk about the purity of things. But actually the more I look at anything, and you look at the origins of where things come from, I think most of the things that actually - if you go deep enough - you find elements of the world within the local. I think that's a big thing to think about, but it actually is reduced to common objects - stories, fables, materials - and silk is also one of those stories."

It's a story that is still with us centuries on, and I think that I'm using the painted panel just as it was intended to be used, as a vehicle for story-telling, to give you my version of the tale of silk. Who used the panel originally we don't know, but we do know that Aurel Stein was surprised and moved by the shrine in which he found it:

"These painted tablets, like all the others subsequently discovered... were undoubtedly still in the same position in which they had originally been deposited as votive offerings by pious worshippers. The last days of worship at this small shrine were vividly recalled by far humbler yet equally touching relics. On the floor near the principal base, and near the corners, I discovered several ancient brooms, which had manifestly been used by the last attendants to keep the sacred objects clear of the invading dust and sand." ('Ancient Khotan', p. 251)

And it was not just the painting of the silk princess that these brooms kept clean. This Buddhist shrine also contained painted images of the Buddha, as well as the Hindu gods Shiva and Brahma. Other shrines in the complex have pictures of Buddhist, Hindu and Iranian gods, as well as very local deities. The gods that travelled the Silk Road were, like the traders themselves, happy to share accommodation.

In this programme, we've been in the company of a legendary princess, uncovering the meaning of her story. Next week we will be with other princesses and great ladies - real ones - praying and plotting, suffering and singing, in the courts of the world's great powers around 800 AD.

And we'll begin with an extraordinary tale of blood-letting, a long way from the Silk Road... we'll be with a Maya queen, in Mexico.