The ancient Romans were passionate about emeralds. As the Roman writer Pliny the Elder declared in his first-century C.E. Natural History, “[T]here is no stone, the color of which is more delightful to the eye, … no green in existence of a more intense color than this.”

Researchers have long known that Wadi Sikait, a valley in Egypt’s Eastern Desert, housed a key Roman emerald mining operation. Now, reports Judith Sudilovsky for the Jerusalem Post, excavations at the site—called Sikait—have revealed the first evidence of the Roman army’s direct involvement in both the construction and defense of the mines. The findings also indicate that the Blemmyes, a rival nomadic group originating in Lower Nubia, may have wrested control of the mines from the Romans between the fourth and sixth centuries C.E.

Per a statement, an international team led by Joan Oller Guzmán, an archaeologist at the Universitat Autònoma de Barcelona (UAB), finished its fifth dig season at Sikait in January. Over the past two years, the researchers have studied sections of the site dated to the tail end of mining activities, around the same time as the Blemmyes’ possible takeover. In the so-called Large Temple, they discovered two perfectly preserved sanctuaries, one of which held an intact votive offering dated to the fourth or fifth century.

“The discovery confirms the relevance of religion and local rituals in this late period, and this suggests that the exploitation of the mines may have fallen into the hands of the Blemmyes during this time, before the fall of the empire,” says Joan Oller in the statement.

The archaeologists concluded that some of the late antiquity buildings were either occupied or built by the Blemmyes—a conclusion supported by the writings of Greek philosopher Olympiodorus. As the team reported in the Journal of Near Eastern Studies last April, “a permit from the king of the Blemmyes was required to enter the emerald mines in the fifth century.”

During the 2020 and 2021 dig seasons, the researchers surveyed 11 extracting areas at the site. They then conducted a detailed topographic study of the two primary mines. One is made up of hundreds of smaller galleries and reaches depths of more than 130 feet.

Investigations revealed a large logistical operation at Sikait, with settlements, necropolises, ramps, paths and watchtowers surrounding the mines, writes Mustafa Marie for Egypt Today. A building called the Tripartite is believed to have been used as a residence and repository for the precious stones.

According to the Jerusalem Post, Sikait and its surrounding environs were the only areas in the vast Roman Empire where emeralds could be mined. The region was known as Mons Smaragdus, or “emerald mountain” in Latin.

In the Roman Empire, emeralds were used regularly in fine jewelry, including earrings and necklaces. Per the Johns Hopkins Archaeological Museum, the Romans associated the gemstone with fertility and healing.

The Blemmyes, also known as the Beja, were pastoral nomads based in northeast Africa, occupying the eastern deserts of Sudan, Egypt and possibly Eritrea. They posed a long-standing threat to Roman-occupied Egypt, constantly raiding settlements and harassing travelers.

“To the Roman colonizers,” wrote Gudrun Dahl and Anders Hjort-af-Ornas in the Nordic Journal of African Studies in 2006, “the Blemmyes/Beja were a real problem. … The Roman garrison was forced to evacuate its positions several times, until [it] finally had to completely abandon the area south of Aswan to the Blemmyes and Nobadae.”