DNA from an ancient grave reveals the Black Death’s patient zero

A Knight’s Tale is a classic story of medieval adventure following William Thatcher (Heath Ledger) as he attempts to win riches, glory, and honor in a series of jousting tournaments. It’s unclear precisely when the movie takes place, largely because it incorporates elements from several centuries of medieval life. However, the presence of Geoffrey Chaucer and Edward the Black Prince, both of whom were real people, pin it down as sometime in the second half of the 14th century.

Among the many challenges Thatcher and his merry band have to overcome, a deadly disease pandemic isn’t one of them. But while the Black Death doesn’t play a large role in the movie, the mid-14th century is right around when the European continent was rocked by it. Now, thanks to a recent study published in the journal Nature, we know where and how it began.

In 1880, a team of Russian scientists excavated the graves of 118 people who died of an unknown disease. The graves were located at Lake Issyk-Kul in what is now modern-day Kyrgyzstan and markers at the graves have been dated to either 1338 or 1339, precisely when scientists expect the Black Death to have emerged. What’s more, inscriptions on some grave markers note pestilence as the cause of death.

Skulls from those excavated graves have been stored at Peter the Great Museum of Anthropology and Ethnography in Saint Petersburg. Prior to this new study, it was unclear what caused the deaths. Having died centuries before the emergence of germ theory, pestilence was often a catchall for any number of ailments. It wasn’t until Maria Spyrou and Johannes Krause from the Department of Archaeogenetics at the Max Planck Institute for the Science of Human History caught wind of the remains that they suspected they might hold the key to the emergence of the Black Death.

Along with collaborators from the museum where the bones were stored, they tested the centuries-old DNA from the teeth of the pestilence victim and confirmed the presence of Yersinia pestis, the bacteria that causes bubonic plague, in three of them.

Moreover, an analysis of the bacterial DNA revealed it to be the most recent common ancestor from just prior to a major diversification event which sparked the pandemic. While that ancestral strain was responsible for at least some of the deaths at Issyk-Kul, one of its descendants raged across the European continent a little less than a decade later and continued to do so, on and off, for the next five centuries.

Scientists believe these 118 people hold within them the starting point for what would become one of the deadliest disease pandemics in human history, killing at least 25 million people over the next couple of decades and tens of millions more centuries later. The plague's severity even spawned an unusual palliative from Isaac Newton, himself.

Not unlike more modern disease pandemics, the evidence also supports the hypothesis that the disease first took root in non-human animals, before making the jump to humans. Once that happened, even our medieval level of global travel allowed the disease to quickly spread, likely finding passage on ships.

While the Black Death is largely contained now – with only about 1,000 to 2,000 reported cases globally each year and a mortality rate of between 8% and 10% according to the World Health Organization – the study authors report that strains still infect dozens of non-human animals, and all of those strains can be traced back to this one progenitor in 14th-century Kyrgyzstan.

Thus began the most intense and deadly microbial jousting match in human history. So far, at least, it looks like we’re winning. We have to admit though that Black Death would make a killer knight nickname.