Archaeologists found a human brain, about 2,600 years old, preserved in oxygen-free clay-rich mud at an Iron Age site near York, England, in 2009.
Researchers at the York Archaeological Trust found the brain intact inside a decapitated skull, which had its jaw bone and two vertebrae attached, in Heslington, York.
The skull was found positioned face-down, without the rest of the body, in a muddy clay-rich pit that provided an oxygen-free burial micro-environment.
Researchers who found the skull first considered it an unremarkable discovery. But while they cleaned the bones, they found a “bright yellow spongy” material inside the skull.
According to Rachel Cubitt, the Collection Projects Officer, she found a “bright yellow spongy material” inside the skull when she peered through a hole at the base of the skull as it was being cleaned.
“I peered through the hole at the base of the skull to investigate and to my surprise saw a quantity of bright yellow spongy material. It was unlike anything I had seen before.”
Scientists at the University of Bradford examined the material and confirmed that it was an intact brain tissue. Experts at the York Hospital’s Mortuary removed the top of the skull to recover the astonishingly well-preserved but shrunken human brain.
Following its discovery, scientists have conducted radiocarbon dating tests to determine the age of the brain. They have also conducted studies to explain why the brain tissue was preserved in remarkably good condition for so long.
Radiocarbon dating tests conducted on a sample of the jaw revealed that the age of the brain was about 2,600 years, meaning that the man lived around the 6th century B.C., about the time of the ancient biblical prophets. This makes the brain probably the oldest intact human brain ever found.
Based on evidence from his teeth and shape of his skull, the man’s age at the time he died was estimated between 26 and 45.
Experts concluded from studies that the brain was preserved partly because the owner was buried in a sealed, oxygen-free, wet clay pit immediately after he met a violent death by decapitation. The clay-rich mud that covered the brain created an oxygen-free micro-environment. The unique conditions resulted in the brain shrinking considerably as fats and proteins linked to form a mass of large complex molecules.
But despite the considerable shrinkage, the brain was able to preserve its overall shape and original microscopic features.
Researchers are uncertain about other factors that might have contributed to the remarkable state of preservation of the brain. Questions arise because other tissues of the skull, including the skin and flesh, have decomposed completely. Only the brain inside the skull showed no signs of putrefaction.
According to experts, it is extremely rare to find soft tissues preserved in that manner.
The nature of the trauma to the vertebrae showed that the man died from a violent blow to the neck. His head was then severed quickly using a small sharp cutting edge. The severed head was buried immediately in a pit dug in clay-rich mud.
Sonia O’Connor, a research fellow at the University of Bradford’s Archaeological Sciences, who studied the skull and brain, said that the condition of the brain indicated that the head was buried immediately after death.
“The hydrated state of the brain and the lack of evidence for putrefaction suggests that burial, in the fine-grained, anoxic sediments of the pit, occurred very rapidly after death. This is a distinctive and unusual sequence of events, and could be taken as an explanation for the exceptional brain preservation.”
Archaeologists can only speculate on why he was killed, his head severed and buried separately from his body. He could have been killed in battle, executed as a prisoner of war, a criminal, or even a sacrificial victim in a religious ritual ceremony.
Earlier suggestion that his head was severed from his body during execution by hanging has been ruled out due to forensic evidence that the head was severed with a sharp-edged instrument.
Suggestion that his head was used as a trophy has also been ruled out because there was no evidence of attempts to preserve the head through treatments, such as smoking, for the purpose of use as a trophy.
[Images: University of York]