That 800-Year-Old Corpse in the Well? Early Biological Warfare.

 Archaeologists in Norway have confirmed that an ancient set of human remains known as the Well Man were intended to make the locals unwell.

The Well Man was little more than a myth until 1938, when archaeologists excavated an abandoned well in the ruins of Sverresborg, outside Trondheim in central Norway.Credit...Norwegian Institute for Cultural Heritage Research

In the dying days of the 12th century, with Norway in the grip of civil wars, the Baglers, a faction aligned with the archbishop, laid siege to Sverresborg, the castle stronghold of King Sverre Sigurdsson. The monarch was away, so the besiegers pillaged the castle, burned down houses and poisoned the water supply by heaving the corpse of one of the king’s men headfirst down the well and filling the shaft with stones, nytimes.com.

This early biological warfare is recorded in “Sverris Saga,” a contemporaneous biography of the king, who reigned over much of Norway from 1184 to 1202. Scholars have long debated the chronicle’s reliability as a historical document, but a study published Friday in the journal iScience recounts how researchers unearthed the body of the “Well Man” and, with the help of ancient DNA, have provided fresh details about who he was.

“This is the first time that the remains of a person or character described in a Norse saga has been positively identified,” said Michael D. Martin, an evolutionary genomicist at the museum of the Norwegian University of Science and Technology. “It is also the oldest case in which we have retrieved the complete genome sequence from a specific person mentioned in a medieval text.”

The Well Man was little more than a mythical fall guy until 1938, when archaeologists excavated an abandoned well in the ruins of Sverresborg, outside Trondheim in central Norway. At the bottom of the layers of dumped stone, some 21 feet down, they found well-intact human remains. But researchers lacked the technology to do more than just a visual survey.

“There are no records of the dig apart from one photograph,” said Anna Petersén, an archaeologist with the Norwegian Institute for Cultural Heritage Research in Oslo. “There are no date books, no journals, nothing. But the Well Man was there.”

Excavations conducted 70 years after the Well Man’s discovery, together with radiocarbon dating, determined that the individual had lived 800 years ago and was a male, 30 to 40 years old.Credit...Norwegian Institute for Cultural Heritage Research

During World War II, research came to an abrupt halt when the German army occupied the area and set up an air defense system on the castle grounds. “The soldiers used the well as a cesspit, cramming it with bottles, shoes, equipment and boulders,” Dr. Petersén said. The Well Man was forgotten.

Another seven decades passed before a second excavation was undertaken. This time the Well Man was partially exhumed. Radiocarbon dating of a shard of his ribs determined that he had lived roughly 800 years ago, a time consistent with the raid described in the saga.

In 2016, a more extensive follow-up project led by Dr. Petersén exposed the timber posts and lining of the well and dredged up the skeleton of a male aged 30 to 40. He was clad in nothing but a perfectly preserved leather shoe, and missing a foot, an arm and a shoulder blade. “To me, he looked as if he had been severely injured prior to being tossed in the well,” Dr. Petersén said. “In the back of his skull was a fresh wound possibly caused by a blow to the head.”

To glean insights into the Well Man’s ancestry, the research team collaborated with deCODE Genetics, an Icelandic company that has compiled one of the world’s most comprehensive collections of population data on genealogy, genotypes and phenotypes. DNA extracted from his premolars suggested that, like pretty much everyone in today’s Norway, he had blue eyes, fair skin and blond or light-brown hair. The geneticists also concluded that his ancestors hailed from the southernmost Norwegian county, present-day Agder.

“Findings such as this make it possible to assess the trustworthiness of ‘Sverris Saga’ and similar texts in new ways,” said Tore Skeie, a Norwegian historian and author, “making us better at reading and evaluating the majority of texts that have not and will never be underpinned by archaeological evidence.”

Dr. Martin was most surprised by the finding that the Well Man had had roots in the south, which is home to his presumed killers, the Baglers. “It goes to show that you can’t couple genetics with political association,” he said.

One question that the new paper does not address is how to interpret the line in the saga about throwing the corpse “headfirst” into the well. The dead man’s cranium was discovered a few feet from the rest of him. Was the corpse plunged into the water upside down or was he decapitated and dropped in, head first, body second?

“All we can say for certain about this anonymous individual is that he was a victim of brutality,” Dr. Petersén said. “ I think that we have at least provided him with an identity and a history that no one really knew before.”