Spanish researchers have identified Europe’s oldest known sandals and uncovered the first direct evidence of basketry in hunter-gatherer societies of southern Europe. Using carbon-14 dating, the team estimates the baskets are roughly 9,500 years old—2,000 years older than previously thought—and the grass shoes could date as far back as 6,200 years.
“My first reaction was, ‘Oh my God, that is not possible,’” lead researcher Francisco Martinez-Sevilla, who studies prehistory at the University of Alcalá in Spain, says to the New York Times’ Rachel Chaundler. “When we realized the magnitude of the findings, we published the paper with all the analysis in less than a year.”
The new paper, published last week in the journal Science Advances, dated 76 objects found during 19th-century mining activities in the Cueva de los Murciélagos, which translates literally to cave of the bats, near the city of Granada, Spain. The prehistoric items were made from organic materials including wood, reed and esparto, or Stipa tenacissima, a grass crushed to make twine.
Archaeologists previously thought the woven baskets were made by farmers from the Neolithic period, when humans began living a more settled lifestyle, because they were intricately decorated with geometric motifs, made with dyed fibers and even adorned with human hairs or pigments, per the study. But the carbon-14 dating determined they were made during the Mesolithic era, or Middle Stone Age, when hunter-gatherer lifestyles were still prevalent.
“The quality and technological complexity of the basketry makes us question the simplistic assumptions we have about human communities prior to the arrival of agriculture in southern Europe,” Martínez-Sevilla says in a statement. “This work, and the project that is being developed, places the Cueva de los Murciélagos as a unique site in Europe to study the organic materials of prehistoric populations.”
Most of archaeologists’ knowledge of past societies comes from the discovery of items more durable than grass and wood, write the authors. In southern Europe, well-preserved artifacts made from organic materials are rare and limited to a few sites where objects have either been charred, waterlogged or desiccated (undergone extreme drying).
But plant-based artifacts give archaeologists insight into cultural and technological traditions, trade networks and human-environmental relationships. This new research provides “a unique opportunity to study social aspects of early human groups,” as study co-author María Herrero-Otal, a physical anthropologist at the Autonomous University of Barcelona, tells CBS News’ Duarte Dias.
Cueva de los Murciélagos has turned out to be a hotbed for artifact preservation because of its lack of humidity and dry, cooling wind that prevents the growth of bacteria. The cave was first accessed in 1831 by the owner of the surrounding lands, who was looking for bat guano to use as fertilizer, per the study. When the mineral galena, an ore of lead, was found in the cave, miners began excavating in 1857. This led to the discovery of a gallery with partially mummified human remains, baskets, tools and other archaeological objects.
But mining activities led some of the plant-based artifacts to be burned and scattered outside of the cave; some baskets and other objects were distributed among nearby villagers. Ten years later, archaeologist Manuel de Góngora y Martínez visited the cave, gathered archaeological remains and collected testimonies about the artifacts from the miners. He published his findings in 1868, but any information on how the artifacts were historically positioned was lost when they were moved from their original locations.
The new research “expands our understanding of the technologies of foraging peoples at the time,” Katina Lillios, an anthropological archaeologist at the University of Iowa, who was not involved in the study, tells the Times. “The preservation at the site of Cueva de los Murciélagos is truly remarkable… and it is great to see that archaeologists have been able to date a larger sample of the plant-based artifacts found there.”
Next, the researchers hope to find out the age of the human remains from the cave using carbon-14 dating, per the Times.