Why Did Each Country Name Syphilis After Its Neighbor?

In February 1495, the army of King Charles VIII of France marched into Naples without a fight. This force of nearly 50,000 men was a patchwork of mercenaries from Flanders, Gascony, Switzerland, Italy, and Spain, trailed by close to 800 camp followers — cooks, medical attendants, and prostitutes who traveled with the army.^[1] The soldiers occupying Naples spent several months there, celebrating their victory. But before the year was out, a strange disease began spreading among them. When the French army disbanded and the men scattered back to their home countries, the disease traveled with them across Europe.^[1]

This disease would later be called syphilis. What’s striking is that during its first few decades, almost no country called it by its own name. Instead, each nation pinned the name on a neighbor — usually one it feared or resented. Lay these names out on a map, and, unexpectedly, they trace the disease’s actual route of transmission.

Blaming the Neighbors: A Map of Syphilis’s Names

The first name to catch on was the “French disease.” Across most of Europe — Italy, England, Poland, Germany — people called it morbus gallicus, the French disease, believing it had come from the French troops stationed in Naples.^[2] The French themselves, however, called it the “Naples disease” (mal de Naples), insisting the disease had already been in that city before they ever invaded it.^[2]

This game of mutual blame played out again and again across Europe. The Dutch called it the “Spanish disease,”^[2] and the Russians called it the “Polish disease.” The Poles, in turn, called it the “Turkish disease,” while the Ottoman Turks called it the “Christian disease.”^[2] Like a hot potato passed from hand to hand, the disease’s name flipped toward whichever country lay across the nearest border. In the Ottoman Empire it was also known as frengi, from frenk, a word that originally meant “Frank” but by Ottoman times had come to mean “European” in general.^[3] To the Ottomans, in other words, this wasn’t a disease from any one nation — it was simply the disease “from Europe.”

The same pattern repeated once the disease crossed from Europe into Asia. In India, it was called firangi rog — literally “the Frank’s disease” — from firangi, a Persian-derived word used generally for Europeans; it also went by the nickname “Portuguese disease,” since Portuguese merchants and sailors were blamed for carrying it into Indian ports.^[4] In Canton, the Chinese port city with the busiest contact with Europeans, the first record of the disease appears in 1505; Chinese sources described it as “Canton sores.”^[5] And in 1512 — not even twenty years after the disease first appeared in Naples — it reached Japan. The Japanese called it the “Chinese sore” (唐瘡, literally “sores from China”) or the “Ryukyu sore” (琉球瘡, “sores from Ryukyu”).^[5] Korea recorded the disease around the same period: the scholar Yi Su-gwang, writing in the early seventeenth century in his Jibong yuseol, called it cheonpochang (天疱瘡) and noted that it had arrived by way of China around 1510.^[6] The names differed from country to country, but they all pointed in the same direction — toward wherever the disease seemed to be flowing in from.

Crossing Eurasia in Twenty Years

Line these names up in chronological order, and a remarkable picture emerges. A disease that began in Naples in 1495 reached the islands of Japan in under twenty years — seventeen years, to be exact. That is a rate of spread that would be no small feat even with modern transportation; this disease managed it on nothing but sails and footsteps.

The likely route runs as follows. In the years right after Naples, soldiers scattering home carried the disease across France, Germany, Switzerland, and England in the late 1490s. By 1496, woodcut broadsides warning of the disease were already circulating in German-speaking Europe — a measure of just how fast it spread.^[7] Then, in 1498, Vasco da Gama’s fleet opened a new sea route linking Europe to the Indian Ocean. Portuguese merchants and sailors began settling along India’s west coast, and the disease followed close behind them.^[5] From there it moved through Southeast Asian ports to the southern coast of China, leaving its first record in Canton in 1505. Seven years later, in 1512, trading ships running between China and the Ryukyu Kingdom carried it on to the islands of Japan.^[5]

How could a sexually transmitted disease travel so far, so fast? First, syphilis stays contagious for a long time. Left untreated, infectious lesions can come and go for up to about a year after infection.^[8] Unlike diseases that burn out within weeks, it could survive a months-long voyage and still arrive alive at the next port. Second, the first people to catch it were the ones who moved the farthest. The army at Naples was made up of mercenaries from across Europe along with some 800 camp followers, and sailors and merchants soon followed.^[7] Third, early syphilis was far more severe than the disease we know today. Ulcers spread across the whole body and deaths were not rare; only after fifty to a hundred years did it gradually grow milder.^[7] Not every route was sexual, either. A wet nurse who suckled an infected baby could catch the disease and pass it on to the next family’s child — a problem that troubled physicians for centuries.^[9]

Whether within Europe or on its way into Asia, the disease’s path tracked, almost exactly, the trade routes and war routes of the age. And the names each region gave it were like arrows pointing backward along that path: Naples, France, Spain, Poland, Turkey, Portugal, China, Ryukyu. But follow those names far enough, and instead of converging on some presumed point of origin, all you find is an endless chain of Europeans blaming one another. So where did this disease actually begin?

Did Columbus Bring It? A 500-Year Debate Over Origins

For centuries, this question had two opposing answers.

The first is the “Columbus hypothesis.” Christopher Columbus’s fleet returned to Spain in the spring of 1493 after his first voyage. Just one or two years later, in 1494–95, the disease made its first large-scale appearance in Naples. Scholars at the time immediately noticed this coincidence in timing. There are also records that some of Columbus’s sailors later fought as Spanish mercenaries in Charles VIII’s Naples campaign, which by the early sixteenth century had already fueled a widely circulated explanation: that these sailors brought a disease contracted in the Americas back to Europe.^[10] Indeed, the Spanish naturalist Gonzalo Fernández de Oviedo, writing in 1526, and the Barcelona physician Rodrigo Ruiz Díaz de Isla, writing in 1539, both explicitly stated that the disease had come from “the Indies” (las Indias) — meaning not the East Indies of Asia, but the West Indies that Columbus had reached, the Caribbean.^[10]

The second is the “pre-Columbian hypothesis.” Starting in the late twentieth century, some researchers argued that certain medieval skeletons unearthed across Europe showed the distinctive bone lesions that syphilis leaves behind. The most famous case involved skeletons excavated from a monastery site in Hull, England, which researchers claimed predated 1493 and bore signs of syphilis.^[11] But this claim soon ran into strong rebuttal. A closer look at the radiocarbon dating of these skeletons showed margins of error wide enough that a date after 1493 could not be ruled out. In fact, every one of the dating ranges for these skeletons comfortably included 1493 within its span, and no case ever emerged that could be pinned down with confidence to an earlier date.^[11] Similar claims surfaced in Greece and Turkey, but they too drew criticism — this time over whether the lesions in question were even caused by the syphilis bacterium in the first place.^[11]

The decisive turn in this debate came from ancient DNA analysis. In December 2024, a research team that included scientists from the Max Planck Institute for Evolutionary Anthropology reconstructed five ancient genomes of syphilis-related bacteria from human bones excavated in Mexico, Peru, Argentina, and Chile, publishing the findings online ahead of print in the journal Nature, with formal publication following in 2025.^[12] Radiocarbon dating placed these skeletons in the thirteenth through fifteenth centuries — mostly predating Columbus’s 1492 voyage. Using molecular-clock methods, the team further estimated that the common ancestor of the entire Treponema pallidum lineage — which includes not just syphilis but its close relatives, the bacteria behind yaws and bejel — dates back as far as roughly nine thousand years. This is a separate estimate: not the age of the individual skeletons, but how far back the bacterial lineage as a whole extends in evolutionary terms.^[12] Based on these two strands of evidence, the researchers concluded that every genetically confirmed member of the Treponema pallidum group identified to date originated in the Americas.^[12] It’s worth noting, though, that this study covered not just the bacterium that causes syphilis specifically, but an entire bacterial group that includes its close relatives, such as those behind yaws and bejel. So the more specific question — exactly when and by what route syphilis itself first landed in Europe — remains open for further research. Even so, this study is widely regarded as the strongest physical evidence yet in favor of an American origin.

There is also evidence pointing the other way. In 2022, a Chinese research team examined more than 1,500 skeletons from a cemetery near Chang’an (modern Xi’an), the capital of Tang-dynasty China. Three of them showed the characteristic bone damage that treponemal disease leaves in its late stages, and radiocarbon dating places these people between 656 and 1147 CE. That suggests a disease of this family may have been present in East Asia — neither Europe nor the Americas — centuries before Columbus.^[5] Given Chang’an’s climate and urban setting, the researchers judged syphilis more likely than yaws or bejel. But they also acknowledged that bones alone cannot reliably tell the three apart, and their diagnosis rests on skeletal changes rather than DNA. So rather than overturning the Columbian hypothesis, the find raises a different question: whether diseases of this family were already scattered across the world before the 1490s.

Looking back, it’s a fittingly ironic ending. For centuries, European and Asian countries pinned the blame for this disease on one another — yet the latest genetic evidence points to the one continent that never appeared among Europe’s and Asia’s names for it: the Americas. That finding, though, isn’t a basis for assigning “blame” to any place or people — a pathogen’s evolutionary origin is a geographic fact, not a verdict on the people who happened to live alongside it. The genetic evidence points to the Americas as the home of the Treponema pallidum family — but exactly how, and when, it crossed to Europe to become the syphilis we know today remains an open question.

The Name Syphilis: Fracastoro’s Shepherd

The English word “syphilis” didn’t appear until more than three decades after the disease had already spread across Europe. The Italian physician and poet Girolamo Fracastoro published a long Latin poem in 1530 titled Syphilis, sive morbus gallicus — “Syphilis, or the French Disease.”^[13] As the title shows, he too initially used the existing name, “the French disease.” But the poem introduced a character who would eventually give the disease its lasting name: a shepherd named Syphilus, who, as punishment for insulting the sun god, is afflicted with sores covering his entire body.^[14]

Fracastoro’s choice to adopt this fictional character’s name as the disease’s name was no accident. As a physician, he wanted the disease treated as a neutral, scientific term, free of the political stigma that came from being tied to a particular nation or people. A name borrowed from a mythical figure blamed no one — not France, not Naples, not Spain. Even so, it took another three hundred years for the name to actually catch on. Well into the early nineteenth century, Europeans were still routinely using the old names — “the French disease,” or simply “the pox.”^[14]

Once it became known that the disease spread through sexual contact, some began devising tools for prevention. The Italian anatomist Gabriele Falloppio described an early linen condom in a 1564 treatise. That story, and the later development of rubber condoms, is covered in detail in The History of Contraception.

Mercury and Guaiacum, and Their Price

Long before Fracastoro gave the disease its name, physicians were already searching for a cure. In 1497, Giorgio Sommariva, a physician in Verona, is credited with being the first to use mercury as a treatment for the disease.^[15] Patients applied mercury ointment to their skin or inhaled its vapor, and treatment could stretch on for weeks, sometimes months. This drawn-out course gave rise to a saying that spread across Europe: “A night with Venus, a lifetime with Mercury.”^[16] Mercury itself, however, was a highly toxic metal. Patients lost teeth, suffered nerve damage, and saw their kidneys fail — and no small number died not of the disease itself, but of mercury poisoning.^[16] The physician Paracelsus later systematized the use of mercury as a treatment for the disease, laying the groundwork for chemical medicine — a story covered separately in The History of Medicine.

Once mercury’s side effects became widely known, a new alternative appeared in mid-sixteenth-century Europe: a decoction brewed from the resin of the guaiacum tree, native to the Caribbean and Central and South America.^[17] Because the wood had to be imported from the New World, it was expensive. Holy Roman Emperor Charles V actually granted the wealthy German banking family, the Fuggers, a monopoly on importing the wood, and the Fuggers aggressively promoted guaiacum treatment, even founding clinics for the poor to help spread its use.^[17] For a while, the treatment seemed to work — but for a different reason than anyone realized. Syphilis moves through a latent phase in which symptoms recede on their own, so no matter what treatment a patient received, there would be a stretch of time when the disease appeared to be cured. Guaiacum’s popularity was, in all likelihood, largely a matter of mistaking this natural remission for a cure.^[18] What’s most striking, in hindsight, is that neither mercury nor guaiacum — nor any other treatment of the era — actually did anything to eliminate the syphilis bacterium itself.

Finding the Bacterium: From the Wassermann Test to Salvarsan

The discovery of the visible bacterium behind this disease came, surprisingly, only in the twentieth century. In 1905, the German zoologist Fritz Schaudinn and dermatologist Erich Hoffmann identified a tiny, spiral-shaped bacterium and named it Treponema pallidum.^[19] The following year, 1906, the German physician August von Wassermann developed a blood test that detected infection by measuring the body’s antibody response to the bacterium. This test, known as the Wassermann test, became the standard diagnostic method in hospitals worldwide for decades to come.^[19]

Finding the bacterium didn’t immediately produce a cure. That breakthrough came out of the laboratory of the German physician Paul Ehrlich. Ehrlich was synthesizing hundreds of compounds in search of a substance that would selectively kill bacteria, and in 1909 his Japanese colleague, Sahachiro Hata, confirmed that the 606th compound they had synthesized effectively eliminated the syphilis bacterium in rabbits.^[20] This compound went to market in 1910 under the name Salvarsan, earning the nickname “magic bullet” as the first chemotherapy agent designed to target a specific pathogen.^[20] Salvarsan, however, was arsenic-based and came with its own side effects, and a full cure still required months of injections.

A true cure didn’t arrive until more than three decades later. In 1943, John Mahoney, a physician with the U.S. Public Health Service, administered penicillin to four patients in the early stages of syphilis. The patients were cured after just eight days of injections — a startlingly fast result compared to the months required by Salvarsan-based treatment.^[21] How Alexander Fleming stumbled on penicillin, and how it became established as an antibiotic, is covered in The History of Medicine. With penicillin, a fight against this disease that had gone on for nearly 450 years could finally be won in a matter of days.

Treatable, Yet Untreated

But having a cure and making sure every patient received it turned out to be two very different things. In 1932, the U.S. Public Health Service began a study in Macon County, Alabama, observing the natural progression of untreated syphilis in roughly 600 Black men.^[22] The researchers never told participants their actual diagnosis, describing it instead only as “bad blood,” and provided no treatment whatsoever. Even after penicillin became widely available in the late 1940s, the researchers continued withholding it and simply kept observing.^[22] The study wasn’t shut down until 1972, when a whistleblower exposed it to the public. By then, at least 28 men had died directly of syphilis, more than 100 others had died of related complications, and the disease had been confirmed to have spread to some participants’ wives and children.^[22] In 1997, U.S. President Bill Clinton formally apologized to the survivors.

Around the same period, the U.S. government was involved in another study, this time in Guatemala. From 1946 to 1948, a research team led by John Cutler, a physician with the U.S. Public Health Service, enrolled more than 5,000 Guatemalan prisoners, soldiers, sex workers, and psychiatric patients in a study. Roughly a quarter of them were deliberately infected with syphilis or other sexually transmitted diseases without their consent.^[23] The study was funded by the U.S. National Institutes of Health, and its existence only came to light in 2010, when a historian happened upon the relevant documents. That same year, the U.S. government issued a formal apology to the people and government of Guatemala.^[23] Both studies took place after effective treatment already existed, and in both, researchers knowingly withheld treatment — or, worse, deliberately caused infection. They stand today as some of the most notorious violations of research ethics in medical history.

Conclusion

The single name “syphilis” sits on top of a whole stack of older names: the French disease, the Naples disease, the Spanish disease, the Polish disease, the Turkish disease, frengi, firangi rog, the Chinese sore, the Ryukyu sore, cheonpochang. None of these names carried any real information about the pathogen itself. What they revealed, instead, was who each namer regarded as foreign and threatening. And yet the one account that came closest to the truth was an offhand claim made without much supporting argument by a handful of sixteenth-century Spanish writers: that the disease came from “the Indies” — meaning the New World Columbus had reached. Five hundred years later, an entirely different method — ancient genetic analysis — would circle back and confirm it as the most likely point of origin after all. Of all the names born from blaming one’s neighbors, the one that came closest to the answer may have been the very first guess.

For English-speaking readers, this history left a couple of distinctly local traces. William Shakespeare wrote the disease into at least fifteen of his plays; in Timon of Athens, a character curses a group of prostitutes with “the hoar leprosy,” and in Troilus and Cressida the go-between Pandarus closes out the play afflicted with the disease himself, lamenting his aching bones and failing health — the era’s most recognizable symptoms, dramatized for a London audience that knew exactly what he meant.^[24] Tuskegee left its own lasting mark on American institutions: the federal panel that shut the study down in 1972 helped drive passage of the National Research Act of 1974, which created the institutional review board system now required for virtually all U.S. research involving human subjects.^[25] That regulatory fix didn’t erase the deeper harm — researchers still point to Tuskegee as one root of the documented distrust many Black Americans hold toward the medical system today.