The volcanic eruption that struck the Roman resort city of Pompeii may be the most famous natural disaster in human history. But one critical detail about the catastrophe continues vexing experts: the precise day, or even month, that it happened. The consensus is that Mount Vesuvius erupted on August 24, 79 C.E., but new research complicates that prevailing notion. Because some Pompeii victims were wearing wool—in the balmy Italian summer.

Experts from ÁTROPOS—a research group studying “the culture of death” at Spain’s University of Valencia—examined 14 of the more than 1,000 bodies that have turned up at Pompeii over the past 250 years. These particular specimens originally surfaced in 1975 at the bygone city’s necropolis near Porta Nola—a huge gate that once ushered guests onto one of Pompeii’s main roads.

Llorenç Alapont investigating the Pompeii casts. Photo: Courtesy of the University of Valencia.

The bodies of those Mount Vesuvius killed are notoriously well preserved today, thanks to volcanic ash and pumice that sealed them away from oxidative decay. The ÁTROPOS crew capitalized on this phenomenon, analyzing the fabrics frozen in time on plaster casts created from said bodies.

The researchers were perplexed to learn that most of the 14 people they examined had been wearing wool when they died. A University of Valencia release regarding the study admits that “wool was the most common and affordable textile of the period.” But, the ÁTROPOS team also noticed that those wearing it had layered up, donning both a wool tunic and a wool cloak. What’s more, four of these people definitively displayed evidence of an exceptionally heavy wool knit. Some of these wool-wearing bodies had surfaced outdoors. Others were indoors. Location didn’t seem to matter.

“The clothing worn by the victims suggests not only the possibility of a colder-than-usual climate, but also a day with a harmful environment from which they needed to protect themselves,” said Llorenç Alapont, an archaeologist, anthropologist, and lecturer at the University of Valencia, added in this week’s release.

Alapont examining another cast. Photo: Courtesy of the University of Valencia.

Although it’s certainly plausible that these victims had bundled up to shield themselves from the heat, gas, and debris generated by Mount Vesuvius’s deadly eruption, it’s hard to ignore the possibility that the detractors could be right—maybe the disaster struck in October, rather than August. After all, “the presence of autumn fruits, braziers containing remnants of embers in houses and wine fermenting in dolia (large clay pots similar to amphorae) suggests that the date could have been later,” the release stated.

In fact, ÁTROPOS debuted its latest revelation at an international congress centered on this very debate. There’s no word yet regarding whether they plan to deepen the discussion by producing a peer-reviewed study, though Alapont did touch on the topic in a paper he helped publish in 2023.