It was a rock about 114.8 feet long, 5.9 feet in height and 9.8 feet deep. Such natural formations occur in the desert, but this large rock was the only one in a large area.

“Its size and shape made it the perfect refuge in a sandstorm,” Castiglioni said.

Right there, the metal detector of Egyptian geologist Aly Barakat of Cairo University located relics of ancient warfare: a bronze dagger and several arrow tips.

“We are talking of small items, but they are extremely important as they are the first Achaemenid objects, thus dating to Cambyses’ time, which have emerged from the desert sands in a location quite close to Siwa,” Castiglioni said.

About a quarter-mile from the natural shelter, the Castiglioni team found a silver bracelet, an earring and few spheres which were likely part of a necklace.

“An analysis of the earring, based on photographs, indicate that it certainly dates to the Achaemenid period. Both the earring and the spheres appear to be made of silver. Indeed a very similar earring, dating to the fifth century B.C., has been found in a dig in Turkey,” Andrea Cagnetti, a leading expert of ancient jewelry, told Discovery News.

Demonstrates that ancient writers might have known what they were talking about.