Ancient miners in southwestern Spain wore sandals made from esparto grass for more than 400 years, a new study shows. Researchers examined eight sandal soles from the ancient mining settlement of Urium in modern Riotinto. The findings show the same style of footwear stayed in use from the Iron Age through the Roman period with few changes.
The study, published in Pyrenae, looked at sandals found in the Nuevo Filón Norte 1 area of the old mining district. Archaeologists recovered the soles from two large ash deposits left after workers cleaned metal furnaces. Those ash layers kept the plant fibers in rare condition for over 2,000 years. Organic objects like these usually rot away, so finds of this kind are rare.
Excavations also uncovered ropes, baskets, and other objects made from plant fibers. These finds give archaeologists a rare look at daily work in one of ancient Hispania’s biggest mining centers. Plant fiber tools rarely survive, so every item adds new detail about how people lived and worked.
Radiocarbon dating showed the sandals came from different periods. One dates to the 1st century CE. Another belongs to the period between the 2nd and 1st centuries BCE. The oldest dates between the 4th and 2nd centuries BCE. The dates show people kept using the same type of sandal for centuries, even as Roman rule spread across the region.
Researchers think the design lasted because it worked well in the rough mining landscape. The sandals likely gave workers better grip and protected their feet while walking across uneven ground. The team links the footwear to the solea spartae described in ancient Latin writings.
The soles were woven from esparto grass, known as Stipa tenacissima. This tough plant grows across southwestern Iberia and has long been used for rope, baskets, and other everyday goods. Close study of the sandals showed skilled workers planned each pair with care. Thick cords formed the parts of the sole that carried the most weight. Finer cords were used for straps and other joining sections.
The team studied the fragile sandals with scanning electron microscopy and X-ray micro-computed tomography. These methods let them inspect the fibers without harming the objects. The scans confirmed the plant species and revealed the braiding patterns in fine detail. Small differences between some sandals suggest more than one artisan made them or changed the design for different needs.
Most soles showed heavy wear around the heel and the front of the foot. Nearly all had lost the cords that once held them in place. Researchers believe the sandals were thrown away only after they wore out and could no longer be fixed. This points to simple work footwear instead of costly personal items.
The collection ranks among the largest groups of Roman-era plant fiber footwear found on the Iberian Peninsula. The sandals offer a rare chance to compare mining sites across ancient Hispania and fill a gap in the study of clothing made from materials that rarely survive.
The study also shows how important plant fibers were in everyday life. Sandals, ropes, and baskets all came from the same raw material. Together, they paint a clearer picture of the people who kept the mines running more than two thousand years ago.