For three thousand years, China kept one secret.
How caterpillars make thread.
5,000 Years of Silk, Secrecy, and Civilization
The Luminous Thread
The Secret Kingdom
Neolithic China → Han Dynasty, 6500 BCE – 200 CE
Silk begins in silence. Sometime around 6,500 years ago, in the river villages of what is now Zhejiang Province, humans began cultivating a relationship with a small, pale caterpillar — Bombyx mori, the silkworm. Archaeological evidence from the Hemudu site shows silk protein residues on artifacts that predate writing, bronze, and every other “civilization marker” except agriculture itself. The Chinese didn't just discover silk. They domesticated the creature that makes it — breeding it over millennia until Bombyx mori became blind, flightless, and utterly dependent on human care. It cannot survive in the wild.
The legend says it differently. According to Chinese tradition, Empress Leizu — wife of the Yellow Emperor — was drinking tea beneath a mulberry tree around 2700 BCE when a silkworm cocoon fell into her cup. As she retrieved it, a single filament unwound. She followed the thread, and in following it, discovered sericulture.
The legend is almost certainly myth — the archaeological record puts silk use three thousand years earlier. But the myth itself is historically significant. For millennia, it was used to justify silk as China's civilizational gift to the world. Annual Leizu worship festivals still occur in Yanting County, Sichuan.
The State Secret
What China built around silk was not just an industry. It was the most protected trade secret in the ancient world. For roughly three thousand years, China held a monopoly on sericulture — the cultivation of silkworms and production of raw silk. Smuggling silkworm eggs, larvae, or mulberry seeds out of China was punishable by death.
Silk was not merely fabric. It was currency. Han Dynasty soldiers were paid in bolts of silk. Diplomatic gifts between kingdoms were measured in silk weight. Tax payments were rendered in silk. The Chinese character for silk, 丝 (sī), became one of the most common radicals in Chinese writing — appearing in characters for “thread,” “weave,” “fine,” and “organization.” Silk was woven into the language itself.
Zhang Qian Opens the Road
In 138 BCE, Emperor Wu of the Han Dynasty sent a young diplomat named Zhang Qian on a mission west — to forge an alliance with the Yuezhi people against the nomadic Xiongnu who threatened China's northern borders. Zhang Qian was captured by the Xiongnu and held prisoner for ten years. He escaped, completed his mission, was captured again, escaped again, and finally returned to the Han court after thirteen years — with the first detailed Chinese account of Central Asia, Persia, and the lands beyond.
Zhang Qian's intelligence reports didn't just describe foreign lands. They described opportunities. Emperor Wu launched military campaigns to secure the Hexi Corridor — the narrow passage between the Tibetan Plateau and the Gobi Desert — and established the Protectorate of the Western Regions. The routes Zhang Qian mapped would carry silk westward for the next thousand years. A German geographer would name them the Silk Road in 1877.
The Road and the Heist
Sogdian Merchants → Byzantine Espionage → Islamic Silk, 200 BCE – 1300 CE
The Silk Road was not one road. Valerie Hansen, in her landmark 2012 revision, demonstrated that the romantic name — coined by Ferdinand von Richthofen in 1877 — masks a more complex reality: a shifting network of routes where most trade was local relay rather than end-to-end. No single merchant traveled from Xi'an to Rome. Goods changed hands dozens of times, each middleman adding markup and mystery.
But the name captures something real. For the first time in human history, a continuous chain of commercial relationships linked the Pacific coast of China to the Mediterranean coast of Rome. Silk was the commodity valuable enough — per ounce — to justify the journey. And the people who made it work were the ones history almost forgot.
The Invisible Intermediaries
The Sogdians were Iranian-speaking merchants based in Samarkand who dominated Silk Road commerce for over four hundred years, from the 4th to the 8th century. They operated trading networks from Xi'an to Constantinople, translating between languages and cultures, maintaining way stations and warehouses, and physically transporting the goods that connected civilizations.
“The Sogdians left behind letters, contracts, and account books that reveal the mechanics of Silk Road trade in unprecedented detail.”
The Afrasiab murals in Samarkand — discovered in 1965, dating to the 7th century — are the only surviving large-scale portraits of Sogdian merchants. They show dignified men in elaborate robes, conducting diplomatic ceremonies. These were not mere traders. They were the connective tissue of the pre-modern world.
Rome's Obsession
At the western end of these routes, Romans craved silk with an intensity that alarmed their own moralists — and they had no idea where it came from. Pliny the Elder, writing in the 1st century CE, believed silk grew on trees: “The Seres are famous for the woollen substance obtained from their forests; after a soaking in water they comb off the white down of the leaves.”
“So manifold is the labour employed, and so distant is the region of the globe drawn upon, to enable the Roman matron to flaunt transparent raiment in public.”
The Roman Senate tried to ban men from wearing silk: “Let no man disgrace himself by wearing silk.” The ban failed spectacularly. Pliny estimated Rome's annual trade deficit to Asia at 100 million sesterces — a hemorrhage of gold flowing east along the same routes that carried silk west.
The Heist
By the 6th century, the Byzantine Emperor Justinian I faced a crisis. The Persian Sassanid Empire controlled the western silk trade, acting as intermediaries between Chinese producers and Byzantine consumers — and charging ruinous prices. Justinian needed to break the monopoly. The opportunity arrived in the form of two unnamed monks.
“About the same time there came from India certain monks; and when they had satisfied Justinian Augustus that the Romans no longer should buy silk from the Persians, they promised the emperor in an interview that they would provide the materials for making silk so that never should the Romans seek business of this kind from their enemy the Persians, or from any other people whatsoever.”
The monks — likely Nestorian Christians who had lived in Central Asia — promised Justinian they could smuggle silkworm eggs out of China. They traveled east, acquired the eggs (scholars debate whether from China proper or from Khotan), and concealed them in hollow bamboo canes. They returned to Constantinople. The eggs hatched. Byzantium had its own silkworms.
China's three-thousand-year monopoly — protected by death penalty, enforced by border guards, sustained by the world's most sophisticated secret-keeping apparatus — was broken by two anonymous men and a bamboo cane. Their names were never recorded. It is one of history's most consequential anonymous acts.
Islamic Silk
The Islamic conquests of the 7th and 8th centuries brought silk production to Damascus, Baghdad, and Córdoba. Islamic artisans developed a distinctive silk aesthetic — the tiraz tradition, in which Arabic calligraphy was woven directly into silk fabric, merging text and textile into a single art form. The English word “damask” derives from Damascus, where some of the finest Islamic silks were produced.
The Machine and the Mystery
Jacquard → Computing → Jim Thompson, 1804 – Present
The Punch Card Revolution
In 1804, a Lyon silk weaver named Joseph Marie Jacquard perfected a mechanism that would change far more than textiles. His loom used interchangeable punch cards — each card encoding one row of a woven pattern. Stack the cards: program the loom. Change the cards: change the pattern. It was the first programmable machine.
Jacquard demonstrated the loom's power with one of history's great flex moves: a silk self-portrait, woven using 24,000 punch cards. Charles Babbage obtained a copy and hung it in his study. It directly inspired his design for the Analytical Engine. Ada Lovelace made the connection explicit:
“The Analytical Engine weaves algebraic patterns just as the Jacquard loom weaves flowers and leaves.”
The technical lineage is direct, not metaphorical: Jacquard's punch cards → Babbage's Analytical Engine → Hollerith's census machine → IBM → the computer in your pocket. Silk literally helped birth the information age.
The Lyon Workers' Revolt
By 1720, Lyon's silk industry employed over 28,000 workers. The silk that clothed kings was woven by hands that couldn't afford bread. In 1831, the Canuts — Lyon's silk workers — revolted under the banner: “Vivre en travaillant ou mourir en combattant!” (Live working or die fighting!)
“We work sixteen hours a day and yet we lack bread.”
The revolt was brutally suppressed. A second followed in 1834. The Canut revolts are considered a founding moment of the industrial labor movement — workers producing the world's most luxurious fabric, demanding the most basic human dignity.
The American Spy Who Saved Thai Silk
Jim Thompson was an American architect who served in the OSS (the CIA's predecessor) during World War II. After the war, he settled in Bangkok and found the Thai silk industry in terminal decline — traditional weavers were abandoning hand looms for cheaper synthetic fibers. Thompson saw what they couldn't: a global market hungry for exactly what they made.
Thompson single-handedly created a global luxury brand from hand-woven Thai silk. He modernized production methods while preserving traditional weaving techniques. International designers came to Bangkok. Thai silk appeared in Hollywood costumes and New York fashion houses. Thompson's house — a stunning assemblage of six traditional Thai houses — became a cultural landmark.
On March 26, 1967, while on holiday in the Cameron Highlands of Malaysia, Jim Thompson went for an afternoon walk and was never seen again. His body was never found. The theories multiply: a tiger attack, abduction by Communist agents, a CIA operation gone wrong, a staged disappearance. None has been confirmed. His house in Bangkok is now a museum, surrounded by silk.
The Thread Today
Five thousand years after Neolithic villagers first cultivated Bombyx mori, China still produces approximately 80% of the world's raw silk. India produces most of the remainder. The global silk market was valued at approximately $16.9 billion in 2023. The same caterpillar, the same mulberry leaf, the same shimmering thread — now also used in medical sutures, biocompatible scaffolds, and experimental spider-silk synthesis.
The Thread That Remains
A single filament of silk is one twenty-fifth the diameter of a human hair. Under a scanning electron microscope, its cross-section reveals a triangular shape — and it is this geometry, not dye or treatment, that gives silk its shimmer. Light enters the fiber, refracts through the triangular prism, and exits as a spectrum. The shimmer you see in a silk scarf is the same physics that caught firelight in a Neolithic Chinese village eight thousand years ago.
China discovered silk around 6500 BCE. China still makes 80% of the world's silk. That is the longest-running economic dominance in human history. The mulberry tree still grows. The silkworm still spins. The thread still shimmers. But now it runs through the history of espionage, the history of computing, the history of labor, the history of empire, the history of fashion — and one unsolved mystery in a Malaysian jungle.
The caterpillar spins in darkness.
It does not know it is making civilization.
Sources
- C1Hansen, V. (2012). The Silk Road: A New History. Oxford University Press.
- C2Prasad, A. (2024). Silk: A World History. HarperCollins.
- C3Procopius of Caesarea (c. 550 CE). History of the Wars, Book VIII. Trans. H.B. Dewing. Loeb Classical Library.
- C4Needham, J. & Kuhn, D. (1988). Science and Civilisation in China, Vol. 5, Part 9: Textile Technology. Cambridge University Press.
- C5Gong, Y. & Li, W. (2011). "Archaeological Evidence for Early Silk Production in China." Archaeometry 53(4), 697–712.
- C6Metropolitan Museum of Art. "Silk in the Medieval Islamic World." Heilbrunn Timeline of Art History.
- C7Victoria and Albert Museum. "Chinese Silk: A Cultural History."
- C11Warren, W. (1998). Jim Thompson: The Unsolved Mystery. Editions Didier Millet.
- C15Essinger, J. (2004). Jacquard's Web: How a Hand-Loom Led to the Birth of the Information Age. Oxford University Press.
- C16Whitfield, S. (2018). Silk, Slaves, and Stupas: Material Culture of the Silk Road. University of California Press.
- C19de la Vaissière, É. (2005). Sogdian Traders: A History. Brill.
- C22Pliny the Elder (79 CE). Natural History, Books VI and XI. Trans. Bostock & Riley. Perseus Digital Library.