Although it was only one of many products traded, silk perhaps best encompasses the history of economic and cultural exchange across Eurasia along the "Silk" Road. The value of silk gave it particular appeal as a political and religious symbol, it was widely accepted as a currency, and it served as a medium for artistic exchange. The complex history of silk is both well documented and in some ways but poorly known.
When we speak of silk, in the first instance we mean that produced in China, where some time probably in the fourth millennium BCE, the Chinese learned the secret of unraveling the fine, rounded filament of the cocoons spun by a worm (Bombyx mori) which fed on the leaves of mulberry trees. There are other species of silk worms (for example, ones native to India), which produce a flatter filament or chew through the cocoon, leaving short fibers. It is the unbroken thread secreted by the mulberry worm which produces the finest fabrics. Silk is almost miraculous in its strength, light weight and insulating characteristics. It provides a medium for writing and reproducing visual images; it is likely that the knowledge of silk processing led to the discovery of how to make paper from plant fibers, another Chinese invention. Early examples of silk fabric preserved in Chinese burials are decorated with "auspicious symbols" suggesting that the fabric had religious significance connecting humans with the natural and supernatural world.
Discoveries in Egyptian tombs indicate that some Chinese silk made its way to the Mediterranean world at least as early as 1000 BCE. The routes of transmission presumably were the same which developed more extensively in later centuries, overland across the heart of Asia or via the coastal trade around Southeast Asia and into the Indian Ocean. In most histories though, the real beginning of the "Silk" Road dates to the establishment of the Xiongnu (Hun) nomadic empire on the northern borders of China around 200 BCE and the development of a relationship between the Xiongnu and the Han Imperial court whereby large quantities of silk were shipped to the nomads to buy peace along the frontiers and ensure the supply of horses and camels for the Chinese armies. This transmission of silk into Inner Asia established the pattern for later centuries, the nomads receiving both finished garments, embroidered or woven with Chinese designs, and raw silk yarn and unfinished cloth.
Striking evidence of the Xiongnu's appreciation for the silk has been uncovered in the royal burials at Noin-Ula in Mongolia, dating from the second and first century BCE. The fabrics discovered there include woolens and silk embroidered with silk thread or decorated with silk appliques. Of particular interest is the fact that some of the embroidery depicts faces of individuals who have distinctly "western" features, suggesting the possibility that even at this early stage in the history of the Silk Road weavers from further west were employed by the Xiongnu in processing the "raw materials" imported from China. Such a pattern of the exchange of craftsmen involved in silk processing recurs throughout the history of the Silk Road. We cannot be certain who were the "westerners" depicted in the Noin-Ula embroidery, but there is substantial archaeological evidence even from some centuries earlier documenting the presence in Inner Asia of people with "Indo-European" features and documenting as well interactions between the Achaemenid Empire of Persia and the peoples of the steppe regions of Southern Siberia and Mongolia.
The quantities of Chinese silk shipped on a regular basis to the nomads down through the centuries were substantial, often tens of thousands of bolts of silk or packages of silk floss annually. Possibly the peak of this exchange was reached in the T'ang Dynasty in the eighth and early ninth centuries, when as much as one-seventh of the government's annual tax revenue paid in silk was being used to obtain horses for the imperial army. The silk was important to the nomads, who acquired a taste for the luxury it provided. The process of building and maintaining a nomadic confederacy of the numerous tribes in the steppe was dependent in part on the ability of the nomadic ruler to distribute on a regular basis to his allies and relatives luxurious silks. Yet it seems quite clear that the quantities of silk sent to the nomads far exceeded their needs. The surplus has to have provided one of the important means for the nomads to acquire other goods they sought by trading the silk to those further west. Thus it is no coincidence that Roman sources from around the first century BCE begin to indicate a sizeable influx of silk into the Roman Empire, within a century or so following the initial agreements by which the Han supplied the Xiongnu with silk on an annual basis. By the first century CE, Roman moralists complained that the taste for the luxury (and for other luxuries imported from the east, such as spices) was bankrupting the empire.
Another factor in the demand for Chinese silk was the spread of Buddhism. From its beginnings in northern India around 500 BCE, Buddhism spread throughout south, central and east Asia. Of particular interest for the history of the Silk Road are the paths which brought that faith into what is now northern Pakistan, Afghanistan, the river valleys of Central Asia and then the oasis cities surrounding the Taklamakan Desert in Xinjiang. The Buddhist communities in these regions were sizeable: travellers such as the Chinese monks Faxian and Xuanzang in the middle of the first millennium CE reported several thousand monks at some of the oasis cities. Some scholars speak of the Buddhist "conquest" of China, where the adherents of the faith at its peak would have numbered in the millions. Silk occupied an important place in Buddhist rituals. Stupas (relic shrines) would be draped in silk and painted silk banners commissioned as donations by laymen. We see examples of these banners in the paintings and relief sculptures of the caves at Yungang and Dunhuang, and many of the striking banners themselves were preserved in the famous Library Cave at the Mogao temples near Dunhuang.
Donations of sizeable quantities of silk guaranteed that prayers would continue to be said for deceased individuals to ensure their favorable rebirth. Graves excavated along the northern Silk Road (for example in the Turfan region) contain lists of objects which presumably were to accompany the dead. However, the large quantities of silk in some of the lists generally were not in fact buried with the dead but seem to represent symbolic (and to a degree, real) donations. There was a belief that silk thread provided a link between this life and rebirth in one of the Buddhist heavens; the symbolic loads of the camels among mingqi, sculpted grave figurines, seem to include bundles of such thread. Buddhist imagery both of holy figures and of laymen being memorialized in the cave temples of places such as Dunhuang, Kizyl and Bezeklik often preserve for us a precise visual record of fabric designs. While Xinru Liu's argument about the causal relationship between the spread of Buddhism and the development of the Silk Road trade may be somewhat forced, there is no denying that a growing demand for silk was connected with the spread of that faith.
Some have argued that the Chinese tried to keep the technique of silk production a closely guarded secret. One of the most striking bits of evidence for this is a small painted board excavated by Aurel Stein at Dandan Oilik, in the Taklamakan Desert not far from the important center for jade export, Khotan. The painting depicts what Stein determined was the story of the "silk princess," who smuggled silk worms out of China in her hairdo when she was sent off to marry the local ruler. The painting clearly is connected with silk production, since it shows some of the implements used; one figure is a possible "god of silk," depicted separately in another of the paintings found by Stein at Dandan Oilik. Whether or not the story of the silk princess is true, there is good reason to believe that silk production did begin in Central Asia by the second or third century CE. A silk industry also developed in the Persian Sasanian Empire, which was founded at the beginning of the third century. Fabrics produced by the Sasanians and Sogdians (the inhabitants of merchant city states in the region around today's Samarkand) were woven with designs based on earlier Persian ones, designs which then would be emulated all the way from Spain to China.
By the sixth century, silk production was established in the Byzantine Empire. According to Byzantine sources, the silk worms had been smuggled from the Middle East by monks--probably Nestorian Christians--who hid them in their staffs. Silk production and trade in Byzantium and Christian Europe had a close connection with the Church, analogous to what we find in the Buddhist world. Clerics would wear silk garments, silk would be used for altar cloths, and silks were preserved in church treasuries. It is largely thanks to some of these pieces that we can learn about silk produced in regions such as the Middle East, where climate conditions have not favored preservation of the fabric. In Byzantium, as in China, silk production was closely regulated by government decree. Sumptuary laws (that is, ones which determined what people of varying status were entitled to wear) were important in maintaining the elaborate hierarcies of these imperial courts. In the case of Byzantium, as much as anything the regulation had to do not with silk itself, but specifically with the silk dyed in the "royal purple." Color and/or design were an integral part of the symbolic status of wearing silk.
The further spread of silk manufacture and consumption from the Middle East on through the West is connected with the rise of Islam, since the early Muslim governments created conditions favorable to economic development and widely ranging international trade. Muslim merchants replaced the Sogdians on the routes of Inner Asia and established large communities in the main cities of China. The Muslim conquest of Spain brought silk manufacture to the Iberian Peninsula in the eighth century. In the Mediterranean world, Jewish merchants played a key role in the silk trade of the Islamic lands. The weaving industries of the Middle East (Syria, for example, was an important textile center) revived and expanded. Islamic rule in North India was probably responsible for the establishment there by the twelfth century of the production of significant mulberry silk production alongside of the existing silk industry based on the native silkworm. As Xinru Liu has suggested, in the Islamic world the use of silk was not so closely restricted as it was in Byzantium or in China. Wearing of silk garments by the elite was widespread, irrespective of rank. What the Islamic governments tended to control, through what was known as the tiraz system, was the weaving in silk of the Arabic inscriptions with the rulers' names, which decorated the borders of textiles.
With so many centers of silk production across Eurasia by the end of the first millennium CE, one might think that the demand for silk produced in China would have disappeared. We know, however, that right down to the Mongol conquest in the thirteenth century, the states on the northwest borders of China continued to receive large quantities of Chinese silk, at least some of which must have been traded to the West. In fact, it seems that most of the centers of production in the West did not supply enough to meet demand there. Moreover, there were always issues of quality, price and style which might support demand for the imported product. The Mongol Empire created what historically were the best conditions ever for the overland trade, as accounts such as that of Marco Polo document. Italian merchants were involved in the China trade, and the development of a flourishing silk industry in Italy in part was thanks to the availability of inexpensive Chinese raw silk. Under the Mongols, silk production in the Caspian provinces of northern Iran also expanded. Imports from that region to the Mediterranean world increasingly were preferred to those from China which often were damaged in the long transit by camel caravan.
The Mongol courts developed a particular taste for a gold-embroidered silk known as nasij, the techniques of whose production originated in the Middle East. The fame of this "Tartar" cloth spread both east and west. Chingis Khan's invasion of Central Asia in 1219 seems to have been occasioned by a dispute involving trade. One important product the Muslim merchants brought to the Mongol court was the cloth produced presumably in Central Asia and Persia. Among the significant activities of the Mongol rulers was to conscript craftsmen from areas they conquered and otherwise to encourage or require technical experts to serve them in regions far from their homes. As sources such as Marco Polo relate, colonies of weavers from the Middle East were established in northern China. There presumably their techniques of embroidery combined with Chinese traditions of silk manufacture to produce the most sought-after textiles. A similar pattern of conscription has been documented for the reign of Tamerlane,the Mongols' successor in Central Asia in the late fourteenth century, who populated his capital Samarkand with merchants and craftsmen, including weavers from Damascus.
By the sixteenth and seventeenth centuries, when the traditional overland trade began to be undercut by political disorders in Central Asia, the focus of European demand for silk shifted to suppliers other than China. A noteworthy example of state support for the silk industry was that of Safavid Persia, especially in the time of its most famous ruler, Shah Abbas I (1587-1629). He promoted the silk industry, the management of which was largely in the hands of Armenians whose commercial center had been moved by the Shah to a suburb of his capital Isfahan. The Dutch and English competed at the shah's court in the early seventeenth century for control of the Iranian silk exports. While hostilities between Safavid Iran and the Ottoman Empire often interrupted the silk trade and forced the Europeans to seek roundabout routes (even to the north, up the Volga River and through Muscovite Russia), eventually establishment of peaceful relations between the two empires ensured that the trade could continue along the historically important overland route to Aleppo and the Mediterranean as well as across Anatolia to the important port of Izmir (Smyrna). The Ottomans themselves developed a silk industry in western Anatolia around Bursa, which to this day is still a center of silk production.
The refinement of mechanized weaving in the industries of the West ultimately would have an impact on production techniques in the East, since mechanized looms required that raw silk meet certain standards of uniformity and quality. Once the requirements of European importers could again be met by Chinese producers, Chinese exports to Europe revived. This process of adaptation by the producers to importers' demands is analogous to that which we see in the Chinese porcelain industry, when it began to produce the shapes and designs which were most sought in the markets of the West.
Given such a complex history of silk production and trade, it is not surprising that determining directions of "influence" on artistic taste in silk fabrics can be quite difficult. One example is the widespread depiction of animals in medallions or roundels, a feature that probably traces its origins to ancient Persia. Fabrics with such designs were produced in Central Asia and the Middle East in the early centuries of the first millennium CE. They became popular in China especially in the T'ang period, when there was a substantial interest in exotica imported from the West. Some of the most striking examples of textiles with such "middle eastern" designs are preserved in the famous imperial treasure house in Japan, the Shosoin. Both in China and on the far western end of the Silk Road, such designs then were incorporated into locally woven fabrics and continued to be produced for several centuries. Often the cloths preserved in the cathedral treasuries of the West contain such striking imagery of lions, peacocks, and hunting scenes. Churchmen seem to have cared little about the fact that imported silk might also bear Arabic inscriptions with Islamic invocations. Silk then was a medium for cultural and artistic exchange which transcended political and religious barriers. Where the weavers themselves moved freely across cultural borders, indeed we may never be able to determine for sure the origins of the pieces of silk which embody the romance and history of the Silk Road.
-- Daniel C. Waugh