In the 19th century, miners in a cave in Southern Spain unearthed a prehistoric burial site containing some 22 pairs of ancient sandals woven out of esparto (a type of grass). The latest radiocarbon dating revealed that those sandals could be 6,200 years old—centuries older than similar footwear found elsewhere in the Iberian peninsula and Europe, according to a new paper published in the journal Science Advances. The interdisciplinary team analyzed 76 artifacts made of wood, reeds, and esparto, including basketry, cords, mats, and a wooden mallet. Some of the basketry turned out to be even older than the sandals, providing the first direct evidence of basketry weaving among the hunter-gatherers and early farmers of the region.
Organic plant-based materials rarely survive the passage of thousands of years, but when they do, archaeologists can learn quite a bit about the culture in which they were produced. For example, last year we reported on the world's oldest known pants, produced in China around 3,000 years ago. With the help of an expert weaver—who created a replica of the pants—archaeologists unraveled the design secrets behind the 3,000-year-old wool trousers that were part of the burial outfit of a warrior now called Turfan Man, who died between 1000 and 1200 BCE in Western China. To make them, ancient weavers combined four techniques to create a garment specially engineered for fighting on horseback, with flexibility in some places and sturdiness in others.
A local landowner discovered Cueva de los Murciélagos ("Cave of the bats") in 1831 and made good use of all that bat guano in the main chamber to fertilize his land. At some point it was also used to house goats, but then the discovery of galena turned the site into a mining operation. As the miners removed blocks to access the vein, they opened up a gallery containing several partially mummified corpses, along with an array of baskets, wooden tools, and other artifacts. Most of the plant-based artifacts were either burned or given to the local villagers.
It was another 10 years before an archeologist named Manual de Gongora y Martinez interviewed the miners about the discovery and collected the scattered surviving artifacts for posterity. He recorded some 68 human remains and assumed the artifacts were associated with those burials: ceramic shards, flint blades and flakes, quartz, a polished ax head, bone awls, ornamental shells, wild boar teeth, and even a gold diadem, as well as the plant-based basketry, sandals, and wooden objects.
According to the authors, the unusual preservation of these plant-based objects is due to the cave's geology. There is almost no humidity, and the Angosturas gorge channels a dry wind current through the cave's narrow upper entrance. As the wind moves through the cave, it cools and dries and increases in speed, thereby making it difficult for plant-hungry bacteria to thrive. Alas, the original positions in which the items were found were never recorded, just that they were recovered from the inner part of the cave. So archaeologists cannot rely on their usual contextual methods to draw definitive conclusions. That said, "The sandals, baskets, and wooden artifacts... constitute a unique sample of organic artifacts absent in other archaeological sites of early farmer communities," the authors wrote.
"The esparto grass objects from Cueva de los Murciélagos are the oldest and best-preserved set of plant fiber materials in southern Europe so far known," said co-author María Herrero Otal of the Universitat Autònoma de Barcelona. "The technological diversity and the treatment of the raw material documented demonstrates the ability of prehistoric communities to master this type of craftsmanship, at least since 9,500 years ago, in the Mesolithic period.”
There are two types of sandals in the Cueva de los Murciélagos inventory: a simple style with no evidence of rudimentary "laces," and a central core style that has fibers protruding from the base of the hole that may have fit between the first and second toes—perhaps used to connect to a braid fixed to the middle of the sandal and tied around the ankle to secure the shoe. The team analyzed both a simple sandal and a central core sandal for their study, which confirmed earlier radiocarbon dating pegging them to the Neolithic period.
Other examples of ancient shoes have been found all over the world: a leather-and-grass shoe found in an Armenian cave dated 3627-3377 BCE; sandals made with lime bast recovered from the Allensbach site in Germany; and the sock-like shoes found with Otzi the Iceman (3350 BCE). But the sandals found at Cueva de los Murciélagos are unique. Not only are they made with crushed esparto—ensuring the sandals are sufficiently flexible to be comfortable to wear—but they significantly predate those other ancient shoes. "This sandal set therefore represents the earliest and widest-ranging assemblage of prehistoric footwear, both in the Iberian peninsula and in Europe, unparalleled at other latitudes," the authors wrote. (UPDATE: Savvy readers wrote in to remind us about the so-called Fort Rock sandals found in an Oregon cave in 1938: flat with a closed toed and twined sole, and dated to about 9,000 years ago.)
There have been prior studies that used radiocarbon dating to analyze the artifacts, most of which concluded that the organic materials dated back to the farming communities of the Early Neolithic period (5200-4850 BCE). However, the authors used a more advanced technique called accelerator mass spectrometry (AMS) radiocarbon dating, combined with Bayesian modeling, and determined that some of the basketry found in the cave dates back to the Mesolithic period, with samples from two distinct phases: the Early Holocene hunter-gatherer population (circa 7500-4200 BCE) and Middle Holocene farmers.
”The new dating of the esparto baskets from the Cueva de los Murciélagos of Albuñol opens a window of opportunity to understanding the last hunter-gatherer societies of the early Holocene," said co-author Francisco Martínez Sevilla of the University of Alcalá. "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."
Science Advances, 2023. DOI: 10.1126/sciadv.adi3055 (About DOIs).
