For centuries historians have debated just exactly where the Black Death — the world’s deadliest plague — originated.

Now, thanks to 14th-century tombstones near Issyk-Kul, a lake in a mountainous area in what is now Kyrgyzstan, scientists claim that they’ve discovered the genesis of the plague that, in the span of eight years, killed 60% of the population in Eurasia.

Led by Wolfgang Haak and Johannes Krause of the Max Planck Institute for Evolutionary Anthropology and the Max Planck Institute for the Science of Human History in Germany, as well as Philip Slavin of the University of Stirling in Scotland, the scientists described their findings Wednesday in the science journal Nature.

TRACKING AN ANCIENT KILLER

While some historians believe the origins of the Black Death began in China, near the Caspian Sea or possibly India, it was Slavin who suggested the team search for clues in a Christian cemetery in Kyrgyzstan.

“I was aware of two Christian cemeteries in Kyrgyzstan and started delving,” he told The New York Times, adding that it was one of his dreams to solve the riddle of the Black Death’s origins

To Slavin’s surprise — and delight — the presence of Yersinia pestis, the bacteria that causes the Black Death, was found in the teeth pulp found in the exhumed remains of three who had died of “pestilence.”

The dates inscribed on the tombstones indicated that the Black Death infected a small settlement of traders in 1338 or 1339.

“That brought it to my attention because it wasn’t just any year,” Slavin said. It was 1338, “just seven or eight years before the Black Death came to Europe.”

Death Comes Unexpectedly

From Europe, North Africa and the Middle East, the Black Death stalked its victims relentlessly.

“The bacteria could be present in people’s homes for between 16 and 23 days before the first symptoms of illness emerged. Death came three to five days later. It was perhaps another week before a community became fully aware of the danger, and by that time it was too late,” wrote the National Geographic UK. “The nodules of a patient’s lymphatic system became infected, showing as swellings in the groin and armpit. These were accompanied by vomiting, headaches, and a very high fever that caused sufferers to shiver violently, double up with cramps, and become delirious.”

Between 1347 and 1351 Europe’s population plummeted from approximately 75 million to just 50 million — roughly 1 in 3 died.

Science Leading the Way

But such discoveries would not have been possible until just over a decade ago.

Unlike other diseases, the Black Death killed people so quickly that it does not leave any traces on bone.

It wasn’t until 2011 that the same group that led the latest study stunned archaeologists by being the first to sequence the genome of the plague bacterium.

Using plague victims from London that had been preserved in the Museum of London, the group of researchers found plague bacteria DNA in the teeth of skeletons.

The situation was ideal because not only were these victims from a plague graveyard, but the date of their death was known, according to The New York Times. From there, the researchers were able to begin building a macabre DNA family tree of the plague bacteria variants — discovering four different Y. pestis strains.

They called the sequencing of the genes “the Big Bang” and sought to find where and when it occurred.

For now, all signs point to Kyrgyzstan and the pulp of teeth for answers.