Name: What Fish Revealed About This Mysterious Grave
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Archaeologists discovered a mass grave of what they thought to be ninth-century Vikings. But for some reason, the radiocarbon dates of their bones, found by measuring a radioactive carbon isotope, appeared much older.

Could these bones be the last remains of a legendary Viking army?

What Fish Revealed About This Mysterious Grave

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Archaeologists discovered a mass grave of what they thought to be ninth-century Vikings. But for some reason, the radiocarbon dates of their bones, found by measuring a radioactive carbon isotope, appeared much older.

Could these bones be the last remains of a legendary Viking army?

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What Fish Revealed About This Mysterious GravePublished: July 8, 2025NARRATOR: This sleepy village in the heart of England was the scene of a gruesome discovery, nearly 300 battle scarred skeletons. Could these be the last remains of a legendary Viking army that swept through medieval Britain? In the 1990, when the archeologists carbon dated those bones, the results were shocking. Many of the bodies appeared to be a century too old to belong to the great Viking Army. A mystery Cat Jarman has been determined to solve.Cat Jarman: Everything that the bones, the artifacts, the coins is really screaming Viking Great Army. But the science, the radiocarbon dates said that's not possible.NARRATOR: Scientists date bones by measuring the amount of Carbon-14 they contain. This radioactive isotope remains in the skeleton after death, it decays over time at a steady rate. So by measuring what's left in the bones, scientists can figure out roughly when the person died.Cat Jarman: What we didn't realize 20 years ago, we actually have to take into account how the carbon that we are dating gets into our bodies. And it actually gets into our bodies through the food that we eat.NARRATOR: It turns out that people with a diet high in fish absorb older carbon than meat-eaters, that's because the oceans contain carbon that is 100 of years old. When fish ingest this, and people in turn eat the fish, the ancient carbon enters their bones. Scientists now know that the bones of people who eat fish appear older than they really are, skewing carbon dating results. Cat has also been able to calculate just how much fish each person has eaten by using the distinctive chemical markers seafood leaves in human bones.Cat Jarman: I looked at all these different bones, and it turned out everybody with a sort of wrong date, as it were, had been eating a lot of fish. That was a really brilliant moment actually, to be able to see those dates fitting perfectly. And that meant the entire mass grave could now be dated to the late 9th century, meaning it's completely consistent with the Viking Great Army.

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