In 1981/2, archaeologists discovered over three hundred bodies on and near the shoreline of Herculaneum. The discovery of these Herculaneum skeletons allowed scientists to establish that those residents who remained in the Roman seaside town during the eruption of Vesuvius died a subtly different death to their neighbours in Pompeii. The final people to die in Pompeii died of thermally induced cadaveric shock, which gave their bodies a pugilistic pose but otherwise left them intact. However,  the people of Herculaneum died instantly, from the intense heat of the pyroclastic surges that swept the town; a heat so intense that it cracked and blackened bones and even caused the victims’ skulls to explode.

Now, Dr Pier Paolo Petrone, a forensic anthropologist at the University of Naples, has revealed in The New England Journal of Medicine,  a new, unique manifestation of these extreme temperatures. For examination and analysis of the skeleton of one individual by Dr Petrone and his team has revealed evidence of vitrification in the skull — meaning the victim’s brain turned to glass. In an interview with History and Archaeology Online, Dr Petrone discusses the implications of this finding to the effects of the eruption at Herculaneum — and the modern-day inhabitants of the land around Vesuvius. 

The Skeleton in the Collegium Augustalium  

Archaeologists discovered the skeleton in question during the 1960s. It was in a small room, in the Collegium Augustalium of Herculaneum, the headquarter’s of the Cult of Augustus, which lies at the junction between Herculaneum’s Decumanus Maximus and Cardo III. 

The body belonged to a 25-year-old man, believed to be the Collegium’s caretaker. He was lying on his stomach on a wooden bed at the time of his death, before being buried by volcanic ash. As with the bodies on the beach and in the boatsheds of Herculaneum, the skeleton was charred and its skull had burst because of the intense heat that caused death. However, there was something unusual about this victim that was only discovered when Dr Petrone and his team began to investigate.  

 A Vitrified Brain 

It is extremely rare for human brain tissue to survive in any archaeological context. If brain tissue is discovered, it is typically saponified — meaning it has broken down into what is essentially soap. However, when Dr Petrone first saw the remains of the victim from the collegium, he realised they were unique — especially when compared to Herculaneum’s victims in the boatsheds, where he excavated between 1997-1999.  

On close examination, Dr Petrone noticed some unusual fragments in the remains of the victim’s skull. The skull appeared to contain a “glassy material” not found anywhere else in the skeleton — or the volcanic ash surrounding it.

Dr Piero Pucci of CEINGE (Centre of Genetic Engineering and Advanced Biotechnology, Naples) examined the fragments using proteomic analysis. He subsequently discovered several proteins found in human brain tissues, as well as human fatty acids and components of human hair. His conclusion was the fragments were the brain of the victim —  turned into glass by the high temperatures that killed him. 

“Vitrification is usually achieved by heating a material until it liquefies, then cooling the liquid quickly so that it passes through the glass transition to form a glassy solid, “ explained Dr Petrone in an interview with History and Archaeology Online.  “This is the same sequence of events that must have occurred in the case of the victim of the College: the brain  — in particular, its fatty acids —exposed to the hot volcanic ash, must have first been liquefied and then immediately converted into a glass-like material by the rapid cooling of the ash deposit.”

Similarities to the Victims of Hamburg and Dresden

The body had a further unusual feature: a “solidified spongy mass” located around the chest bones. “As a part of the victim’s body, the chest bones were completely solidified in a spongy mass, most likely as a result of the melting and crystallisation (solidification) of fatty acids from body soft tissues, as a consequence of exposure to a temperature of about 950 °F [520 degrees centigrade]”, explained Dr Petrone. 

Archaeologists have not discovered this phenomenon on any other archaeological site. However,  it does have a more recent equivalent — in the bodies of firestorm victims from the bombing of Dresden and Hamburg during the Second World War. “There were no real complete bodies, only bones and scorched articles of clothing matted together and stuck together by a  sort of jelly substance.“said Dr Petrone, quoting from an account of an English survivor of the firestorms. “There was no flesh visible, just a glutinous  mass of solidified fat and bones swimming around, inches thick, on the floor”

“A single finding …..due to the environmental conditions”

No other victim in Herculaneum has exhibited either a vitrified brain or the same melting and resolidifying of the skeleton  — despite everyone in Herculaneum dying from the thermal effects of a pyroclastic surge. “Such a single finding is presumably due to the environmental conditions to which the individual was exposed at the time of impact with the volcanic cloud,” said Dr Petrone. He went on to explain how  the skeleton’s unusual features resulted from the fact that “In this case, the effects of the high  temperature are much more severe than in any other victim.”

However, Dr Petrone also explained that the extreme effect on the body in the collegium and the differing “environmental conditions” were not due to a change in the temperature of the surge. Studies of the wooden material in the collegium show that it was subjected to the same temperature range (590-986 Degrees Fahrenheit) — as elsewhere in Herculaneum. Instead, the body owes its unusual features to the fact the victim was alone rather than part of a group.   

“The effects of the high temperature [in the case of the body in the Collegium] are much more severe than in any other victim, possibly due to the fact that in this single case just one body is completely exposed to the intense heat of the volcanic ash and also as a consequence of charring of the bed wood,”concluded Dr Petrone.

So because he was alone and sleeping on a wooden bed that was ignited by the blast, the body of the man in the collegium suffered more extremely from the heat. Dr Petrone also cited other examples of extreme damage due to greater exposure to the surge, pointing out that on the victims in general, the most exposed parts of the body — the head, shoulders and limbs — sustained the most damage from the surge. 

However, the sobering fact remains, that no matter where you were or who you were with, there was no escaping death in Herculaneum in 79AD.  According to Dr Petrone, this fact remains “ A silent warning for the three million inhabitants of metropolitan Naples.”