Trading Silk for Horses: The Surprisingly Simple Origins of the Silk Road

Soft, strong, and shimmering—silk was first cultivated in China, perhaps as early as the mid-third millennium B.C. The art of turning the cocoons of the silkworm moth (Bombyx mori) was, according to legend, discovered by the wife of the Yellow Emperor, a mythical forebear of the tribe that later founded China’s first dynasty, the Xia, in circa 2070 B.C. While she was drinking tea in the shade of a mulberry bush, a cocoon fell into her cup. Instead of throwing it away, she examined it and discovered that pulling on a strand could completely unravel it.

Traditionally, silk production was entrusted to Chinese women and carefully guarded as a state secret. Revealing the confidential methods of sericulture was punishable by death. Centuries later, it would be these silken threads that would weave together a vast trade network, linking the lands of China to Rome.

In the 19th century German geographer Ferdinand von Richthofen looked for a term to describe the trade routes that shuttled silks and other luxury goods between the Far East and the Mediterranean from the first century B.C. until the Middle Ages. It seemed appropriate to name it for the item most associated with Eastern opulence, and Richthofen’s term, “Silk Road,” has stuck ever since.

Beyond the Wall

The Chinese did not make an effort to sell silk outside of their country until circumstances forced them to do so. At the end of the third century B.C., Emperor Qin Shi Huang Di (r. 221-210 B.C.) began consolidating forts in the north, the first phase of what would eventually become the Great Wall. His aim was to halt the incursions of the nomadic Xiongnu tribes. Over time, the wall proved to be insufficient on its own; in 138 B.C. Han emperor Wudi tried another approach. He attempted an alliance with another Central Asian tribe, the Yuezhi, enemies of the Xiongnu.

Zhang Qian, a young officer of the emperor’s palace guard, was appointed as the leader of the diplomatic mission. In order to reach the Yuezhi, he had to enter enemy territory to the northwest and was captured by Xiongnu forces. After a long imprisonment, he returned to China 13 years later, his mission to the Yuezhi a failure.

In this and other subsequent adventures, however, Zhang Qian learned a great deal about the mysterious lands to the west: India and the Parthian Empire, whose lands correspond to northeastern regions in Iran today. In the Fergana Valley, north of the Hindu Kush, he observed horses much larger than those in China. He recognized that these beasts would be valuable military additions to Chinese forces. While in Parthia, he also made contact with the remnants of the Hellenist culture established by Alexander the Great in Central Asia, marking the first major contact between China and Indo-European society. Most important of all, he identified a widespread desire for Chinese silk.

Having absorbed Zhang Qian’s reports after his return, the Han dynasty saw the advantages of westward trade, especially the prospect of obtaining the superior Fergana horses. Officials knew they could trade silk for these horses. In time this trade would plug China into the lucrative markets of the West, including the booming Roman world.

The route did not arise out of a vacuum. In the fifth century B.C. the sprawling Persian Empire had already improved travel through western Asia, while Alexander the Great’s eastward expansion helped lay the foundations of trans-Asian trade. Even so, Zhang Qian’s remarkable adventures were important early steps in creating the Silk Road.

Through Snow and Sandstorms

The Chinese capital, Chang’an (Xi’an), was the eastern starting point of this trading route. Strictly speaking, the Silk Road was not a single highway but a network of roads that twisted and turned on the way from east to west. From Chang’an, for example, one branch went southwest to the mouth of the Ganges in India. Among the luxury products traveling west were jade, turtle shells, bird feathers, and, of course, silk. Traders also brought metals—silver, iron, lead, tin, and gold—and foodstuffs—saffron and other spices, tea, carrots, and pomegranates.

By 102 B.C. the Chinese controlled traffic along the Silk Road as far as the Fergana Valley. Although goods traveled thousands of miles in both directions, the merchants themselves probably only journeyed along short sections. When they reached the next city, they would sell their merchandise to the locals, who then would travel along the next segment and trade with the merchants there. The Dunhuang Oasis was the main Chinese customs post. Westbound traders had to wait several days to pay their exit duties while soldiers carefully searched their baggage to make sure no one was smuggling silkworms or cocoons out of the country.

From there, the westward journey split into three main routes. The two northern roads passed on either side of the Heavenly Mountains (Tian Shan), whose peaks soar to heights of 24,000 feet. The third road went south and passed through Khotan (near modern-day Hotan in China), famous for silken rugs. This route skirted the edge of the almost impassable Taklimakan Desert, where extreme temperatures and sandstorms claimed the lives of many travelers.

The northern and southern roads met again near Kashgar, on the border with modern-day China and Kyrgyzstan. The traders then crossed the Pamir Mountains along narrow snowy tracks, before descending into the Fergana Valley. Somewhere near here they rested in a place the second-century Egyptian geographer Ptolemy referred to only as the “Stone Tower.”

Believed by modern historians to be the city of Taxkorgan, Ptolemy considered it the midway point of the Silk Road. Here, as in other cities along the route, merchants from all over central Asia waited to trade. These included the Sogdians, whose lands centered on the trading city of Samarqand (Uzbekistan), and who became the most prominent of the Silk Road’s middlemen between China and the West. Farther west still, the Parthians thronged the routes that passed through their lands, centered on areas of modern-day Iran, Iraq, and Turkmenistan, where the great trading city of Merv is located.

Parthian kings built caravansaries to accommodate the traders and their camels along the route to Ctesiphon (near Baghdad), their first-century B.C. capital. From here, they crossed the desert wastes of Syria via Palmyra. Having reached the Mediterranean, goods were shipped to Rome from ports such as Tyre and Antioch.

Rome itself had developed a love-hate relationship with silk. One of the earliest recorded observations occurred during a conflict with the Parthians, whose archers soundly defeated Roman troops in 53 B.C. at the Battle of Carrhae in modern-day Turkey. Before the battle, Romans made note of the Parthians’ bold, beautiful spectacle that conveyed power and invincibility as well as finesse: colorful banners woven from Chinese silk. The Roman second-century historian Florus later described the moment when the Parthian generals “displayed all around [the Romans] their standards, fluttering with . . . silken pennons” before describing how the army was slaughtered and its Roman commander killed.

Ever since the shameful rout at Carrhae, silk both troubled and delighted the Romans. A century after the battle, silk was immensely popular across the Roman Empire. This weakness for a foreign luxury was bitterly criticized by Rome’s stern moralists. In the first century Pliny the Elder wrote: “At least a hundred million sesterces flow out of our empire every year to India, China, and Arabia. That is how much luxury and women cost us!”

The Road that Changed the World

In A.D. 220 the Han dynasty collapsed, and China passed through a period of political upheaval. Over the coming centuries, the monopoly on silk that the Han had so carefully nurtured fell apart, and silk production started to spring up outside China. By the sixth century even the Romans had secured their own independent supply after the Roman emperor Justinian successfully smuggled silkworms into his empire.

Since the moment it left Chang’an, to its unpacking in the aristocratic surroundings of a Roman villa about a year later, a roll of silk would have passed through a dazzling array of cultures, languages, and climes. Even though silk production had spread to the western lands, the Silk Road continued to be a vibrant connection of cultures and trade. Not only products traveled along the Silk Road, but ideas too: convulsions in human thought and faith that reshaped the world. Buddhism, Christianity, and Islam would all travel along these paths and touch cultures along the way, shaping people’s beliefs and philosophies over time. In the seventh century, after China returned to growth and prosperity under the Tang dynasty, the route was boosted by renewed Chinese demand for luxury goods from the West, including silver-making techniques, chairs, and ceramics. In part to protect this trade, the Tang embarked on a major expansion westward, even as the first Christian missionaries were moving east along the Silk Road. At the same time, Islam was rising in the Arabian Peninsula, and during the eighth century, it spread farther and farther east along the trade routes.

In A.D. 751 Muslim Abassid troops clashed with the Chinese at the Battle of Talas. This pivotal battle, which checked China’s westward expansion, may have contributed to another, no less significant outcome: According to lore, several of the Chinese prisoners from the Battle of Talas taught their captors a craft, that disseminated through the Muslim lands into southern Europe. The skill these Chinese artisans passed on to their captors was nothing less than how to make paper, which would transform history and how it would be written.