How a shifting network of caravan tracks connected the economies and ideas of East and West
Despite its name, the Silk Road was neither a single road nor devoted solely to silk. The term itself is surprisingly modern: none of the merchants, monks or soldiers who crossed Central Asia in antiquity ever used it. It was coined only in 1877 by the German geographer and traveller Ferdinand von Richthofen, who spoke of the Seidenstraße to describe the web of overland routes that had linked China with Central Asia, Persia and the Mediterranean world for more than fifteen hundred years. Where modern maps often draw a neat line across the continent, travellers on the ground faced a shifting tangle of desert tracks and high mountain passes that branched around shifting sand dunes, dried-up wells and local wars.
Long-distance trade across the Eurasian steppes existed in prehistoric times, but the network expanded dramatically during China's Han dynasty in the second century BC. Troubled by raids from nomadic confederations to the north, the Han court sent an envoy named Zhang Qian westwards in search of allies and of the tall, swift horses bred in the Fergana Valley of Central Asia, which were superior to the smaller ponies native to China. Although Zhang Qian's diplomatic mission met with mixed success, the reports he brought back after more than a decade abroad opened Chinese eyes to sophisticated urban civilisations further west that were eager to trade for Chinese goods.
Chief among those goods was silk. For centuries, the Chinese guarded the secrets of sericulture – the cultivation of silkworms and the reeling of their fine filaments – and imperial law forbade taking silkworm eggs or mulberry seeds out of the country. In the Roman Empire, silk became a symbol of extravagant wealth, worn by patricians and denounced by moralists who complained that Roman gold was draining eastwards to pay for sheer fabrics. Yet silk was also practical inside China and along the frontier: rolls of plain silk were light, durable and easy to pack, and the Chinese government frequently used them alongside coins to pay soldiers at remote garrisons and to buy peace from neighbouring tribes.
Popular imagination often pictures a single caravan setting out from the Chinese capital of Chang'an and unloading its bales in the markets of Antioch or Rome. In reality, almost nobody made the whole journey from end to end. Instead, goods moved in short stages, changing hands repeatedly in oasis cities such as Dunhuang, Samarkand and Bukhara. A bale of raw silk might be carried west from China by one merchant, sold in a desert market town to a Sogdian trader – an Iranian-speaking people from Central Asia who served as the great middlemen of the routes – and then carried further west by Persian or Syrian merchants, with its price rising sharply at every exchange.
Crossing the Taklamakan Desert or the Pamir Mountains demanded careful organisation. Merchants travelled in caravans of dozens or even hundreds of two-humped Bactrian camels, animals uniquely suited to the route because they could carry heavy loads through freezing winter winds as well as scorching summer heat, and could go for days without water. Along the main tracks, rulers and wealthy patrons built caravanserais: stoutly walled roadside inns spaced roughly a day's march apart. Inside a caravanserai's courtyard, travellers could stable their camels, draw water, cook a meal and exchange news about bandits, taxes or mountain snows with merchants speaking half a dozen languages.
Although silk gave the network its modern name, the traffic moved in both directions and carried a vast range of commodities. Moving west from China went not only silk, but also porcelain, lacquerware, iron tools, rhubarb and cinnamon. Moving east into China came Fergana horses, Roman glassware – prized because early Chinese kilns produced high-fired ceramics rather than blown glass – together with woollen carpets, jade from Khotan, frankincense and Baltic amber. Just as consequential were the invisible cargoes. Buddhist monks travelled along the caravan tracks from India through Central Asia into China, establishing cave temples and translating sacred texts at oasis stops, while Christian and later Islamic scholars followed the same paths. Technologies travelled too: the craft of making paper from plant fibres, invented in China, reached Samarkand in the eighth century before spreading to Damascus and eventually Europe.
The overland routes flourished whenever large empires, such as the Tang dynasty in China or the Mongol Empire in the thirteenth century, kept the peace across wide stretches of territory. Conversely, political fragmentation and heavy tolls along the way made caravan transport risky and expensive. From the late fifteenth century onwards, after European mariners charted direct sea routes around southern Africa to India and East Asia, a single ship could carry far more cargo than a camel caravan without paying tribute to a dozen rulers en route. The desert oases did not vanish overnight, and regional trade continued, but the great transcontinental artery gradually yielded to the ocean.