Interesting Facts About Silk: Seven That Sound Made Up

Around 77 CE, Pliny the Elder, who had read about as much as anyone alive, explained to Rome where silk came from: people at the far edge of the world soak leaves in water and comb off the white down. Rome believed it and kept buying.

Silk has been attracting that sort of story ever since, which makes it a fun subject and a slippery one. We started with a longer list and traced each item back as far as we could. These seven held up. Where one is a legend, we say so.

1. One cocoon can hold 16 football fields of thread

A single silk cocoon is one unbroken filament, as long as about 1,640 yards (1,500 meters) at the top of the range, or 16 football fields laid goal line to goal line. The low end, in the UN's silk reeling manual, is still about 650 yards. The caterpillar lays it all down in two or three days, mostly by swinging its head. How silk is made follows that thread from leaf to loom.

2. The silkworm can't survive without us

The domesticated silkworm, Bombyx mori, no longer exists in the wild. After more than 5,000 years of breeding from a wild moth, the adult can't manage real flight, and like its relatives it doesn't feed at all. Without people, the species would be gone. That dependence has a hard side, which is silk cruelty-free? doesn't dodge.

3. Rome paid for silk without knowing what it was

Rome bought silk for generations while most Romans believed it grew on trees. Virgil wrote of the Seres combing fine down from leaves, and Pliny repeated the idea, though elsewhere in the same work he comes closer, describing creatures that weave webs like spiders. "Seres," the Greek and Latin name for the people at the far end of the trade, appears to come from their word for silk, so Rome knew them chiefly as the silk people. Chinese records don't note a Roman embassy until 166 CE.

The fabric worried the Senate. Early in the reign of Tiberius, Tacitus records a decree that "men should not disgrace themselves with silken clothing from the East." The effort failed, and silk kept selling.

4. A legend hides silkworm eggs in a princess's headdress

A well-known legend says a Chinese princess, sent west to marry the king of Khotan, smuggled silkworm eggs in her headdress because the border guards wouldn't dare search her. The monk Xuanzang wrote it down in 646. In 1900–01 the archaeologist Aurel Stein dug up a painted wooden panel at Dandan Oilik, a ruined settlement in the desert near Khotan. On the panel, about 18 inches wide, an attendant points at a woman's headdress. It's now in the British Museum, and Stein took it for this very story.

A legend is what it is. The American Historical Association says silk heists like this are "not rooted in historical reality," though people clearly loved telling them. Who invented silk? covers what the archaeology shows.

5. Nobody on the Silk Road called it the Silk Road

The name "Silk Road" dates only to 19th-century Germany. The geographer Ferdinand von Richthofen usually gets the credit, for using it in 1877, but a 2019 article in the journal The Silk Road found Carl Ritter using Seidenstraße in print in 1838. The first book called The Silk Road, by the Swedish explorer Sven Hedin, appeared in English in 1938. The merchants and monks who traveled those routes for well over a thousand years never heard the phrase.

6. More than a million spiders made one cape

Someone really has woven a garment from spider silk, and it took silk from more than a million female golden orb-weavers. Textile artist Simon Peers and entrepreneur Nicholas Godley collected it in Madagascar, drawing silk from the live spiders and then letting them go. The Victoria and Albert Museum in London showed the cape in 2012. Nobody dyed it. That gold is the color the spiders made.

For scale, a silk pillowcase takes a few hundred silkworm cocoons by our arithmetic, which goes some way to explaining why your closet holds no spider silk.

7. A Tombstone doctor wrote a paper on silk and bullets

In the 1880s, Dr. George Goodfellow of Tombstone, Arizona, began collecting gunshot cases in which silk had held where other cloth hadn't. In 1881 he examined the gunfighter Charlie Storms, shot by the gambler Luke Short, and found one bullet wrapped in two thicknesses of silk from the handkerchief in his breast pocket. After a later shooting, he found two shotgun pellets caught in a silk handkerchief around a man's neck, with no holes in the cloth. The Tombstone Epitaph suggested that "a silken armor may be the next invention," and in 1887 Goodfellow published "Notes on the Impenetrability of Silk to Bullets."

The newspaper wasn't far off. In Chicago, after the 1893 assassination of Mayor Carter Harrison Sr., a Polish-born priest named Casimir Zeglen developed a vest of woven silk that could stop the slow rounds from black powder handguns. Please leave your scarf out of any safety plans. Modern ammunition is another matter entirely.

What about the death penalty for smuggling silkworms?

We couldn't verify that one, so it isn't on the list. Plenty of books and websites say that taking silkworm eggs out of China, or explaining the process to a foreigner, was punishable by death. We looked for the statute, the case or the primary text behind the claim and didn't find one, and even Wikipedia's version carries a "citation needed." It may be true. Until someone produces the document, it's a good story.

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Pliny got the leaves wrong, though in his defense, what actually happens is harder to believe. A caterpillar walling itself in with 16 football fields of thread was never going to sound like the sensible explanation.

Frequently asked questions

How long is a single silk thread?

One cocoon holds a single filament of about 650 to 1,640 yards (600 to 1,500 meters), according to the UN Food and Agriculture Organization's reeling manual. About 80 percent of it can be unwound. That filament is too fine to use alone, so several are reeled together to make one thread.

Why is it called the Silk Road?

The name was given by 19th-century German scholars, after silk, the best known of the goods carried along those routes. Ferdinand von Richthofen is usually credited for 1877, though Carl Ritter used the German phrase in print in 1838. People using the routes at the time didn't call them that.

Can silkworms live in the wild?

The domesticated silkworm, Bombyx mori, can't. It has been bred for more than 5,000 years, doesn't exist in the wild, and the adult moth can't manage real flight. Its wild relative, Bombyx mandarina, still lives outdoors.

Did a princess really smuggle silkworm eggs in her headdress?

It's a legend, recorded by the monk Xuanzang in 646 and shown on a painted panel from Khotan now in the British Museum. The American Historical Association says such stories aren't rooted in historical reality. Silk production did reach Central Asia, by routes and at dates that are still being worked out.

Is silk used in surgery?

Yes. US Food and Drug Administration rules cover natural nonabsorbable silk surgical suture, a sterile thread made of fibroin from the silkworm, as a regulated medical device. That rule applies to sterile surgical thread. It says nothing about scarves, pillowcases or what silk does for your skin.

Related reading: The Stories Behind Silk Scarves