Manure preserved for millennia by the arid climate of Israel’s Timna Valley is adding fresh fuel to a long-simmering debate about the biblical king Solomon and the source of his legendary wealth.

Archaeologists discovered the 3,000-year-old dung in an ancient mining camp atop a sandstone mesa known as Slaves’ Hill. The area is dotted with copper mines and smelting camps—sites where the ore was heated and turned into metal.

University of Tel Aviv archaeologist Erez Ben-Yosef began excavating the site in 2013. Last year he and his team were uncovering the remains of several walled structures, including a fortified gate, when they discovered what appeared to be animal excrement of relatively recent origin.

“We thought maybe some nomads had camped there with their goats a few decades ago,” Ben-Yosef said, noting that the dung still contained undecayed plant matter. “But the [radiocarbon] dates came back from the lab, and they confirmed we were talking about donkeys and other livestock from the 10th century B.C. It was hard to believe.”

While the dung’s extreme age and extraordinary condition were stunning, the implications of the radiocarbon results were even more jarring.

“Until we started the project in 2013, this was considered to be a late Bronze Age site related to the New Kingdom of Egypt in the 13th and early 12th centuries B.C.,” Ben-Yosef says. There’s clear evidence of an Egyptian presence during those centuries, and modern-day visitors to nearby Timna Valley Park are greeted by signs depicting ancient Egyptians.

But high-precision radiocarbon dating of the dung, as well as textiles and other organic material, showed that the mining camp’s heyday was the 10th century B.C.—the era of the biblical kings David and Solomon. (Read "Kings of Controversy".)

According to the Hebrew Bible, King Solomon was renowned for his great wisdom and wealth, and his many building projects included a temple in Jerusalem lavishly appointed with gold and bronze objects. Such a structure would have required large amounts of metal from industrial-scale mining operations somewhere in the Middle East, but the scriptures are silent as to their location.

View Images The Queen of Sheba visits the opulent court of King Solomon in an imagined scene by British painter Edward Poynter. Illustration by Heritage Images, Getty Images

In the 1930s American archaeologist Nelson Glueck (pronounced Glick) announced that he had found the famous mines while exploring the copper-rich Arabah Valley, a geological rift that stretches from the Dead Sea south to the Red Sea and straddles the border of modern Israel and Jordan.

“It is now known that along the entire length of the Wadi ‘Araba there are deposits of copper and iron,” Glueck wrote in an article entitled “On the Trail of King Solomon’s Mines” in the February 1944 issue of National Geographic. “These were intensely worked in ancient times, particularly during the time of King Solomon.”

Searching for Solomon’s Mines Awash in riches from trade and tribute, King Solomon embarked on a building campaign that included his famous temple in Jerusalem. Many of the implements used in worship were made of bronze, requiring much copper to form the alloy. LEBANON EUROPE Beirut ASIA MAP AREA AFRICA Damascus Kingdom of Solomon circa 950 B.C. Copper-mining center SYRIA Sea of Galilee ISRAEL Mediterranean Sea AMMON WEST BANK Tel Aviv-Yafo Amman Jerusalem Nation subject to Solomon Dead Sea GAZA STRIP Beersheba MOAB NEGEV Khirbat en-Nahas JORDAN EGYPT Timna Valley 40 mi 40 km Present-day boundaries are shown. Gulf of Aqaba MATTHEW W. CHWASTYK, NG STAFF

Many archaeologists who followed in Glueck’s footsteps, however, argued that David and Solomon weren’t the powerful kings depicted in the Bible. Instead they were small-scale chieftains incapable of organizing a major mining operation and orchestrating long-distance trade.

View Images Archaeologist Nelson Glueck (second from left) believed he had found Solomon's mines in the copper-rich Arabah Valley of southern Israel and Jordan. Photograph by Dmitri Kessel, The Life Picture Collection, Getty Images

Critics also took issue with the traditional biblical chronology, which places the reigns of David and Solomon in the 10th century B.C. As a result, “Glueck became a laughingstock in the scholarly world,” says Thomas Levy, professor of archaeology at the University of California, San Diego, and a National Geographic Explorer.

But discoveries made in recent decades may turn the tables and vindicate Glueck’s faith in the Bible’s record of events.

In 1997 Levy began a multi-year excavation at Khirbat en-Nahas, a site in southern Jordan that Glueck suggested was an ancient center of copper production. Levy and his team dug through more than 20 feet of copper slag waste to reach virgin soil, indicating that metal had been produced there on a massive scale. “Our excavations are providing support for many of Glueck’s insights,” Levy wrote in 2006.

The recent find in Israel’s Timna Valley may score more points for Glueck, who discovered and named the Slaves’ Hill site in 1934. The mining operation there is not yet linked to Solomon himself, but it does suggest that the region was home to a complex society—most likely the Edomites, the ancient Israelites' antagonists.

View Images Chunks of copper ore come easily to hand in a remote region of Jordan, where archaeologist Thomas Levy excavated an ancient mining center. Photograph by Kenneth Garrett, National Geographic

The accuracy of biblical passages claiming that King David marched his armies deep into the desert to engage the Edomites has long been debated. But Ben-Yosef says the fortified walls he’s found around the smelting camp indicate it was very likely a military target.

If the Bible’s claim that David brought the Edomites to heel is accurate, he may have been in a position to demand tribute, Ben-Yosef says. “There’s a serious possibility that Jerusalem got its wealth from taxing these mining operations.”

Evidence of Long Distance Trade

The dung samples included seeds and pollen spores so intact that Ben-Yosef’s team was able to determine the animals’ diet, which yielded another surprise: The feed was imported from an area more than 100 miles to the north, close to the Mediterranean coast. The distance to Jerusalem is about 190 miles (300 kilometers), a two week trip by donkey in ancient times.

Long distance trade was key to survival at this remote site surrounded by barren desert. Every necessity had to be hauled in on donkeys—even the nearest water source was 12 miles away—making this a complex and costly undertaking.

“Metal in this period was an essential product, similar to the oil of today,” Ben-Yosef says. “So it was worth these peoples’ while to invest so much in this operation in the middle of the desert.”

More than 1,000 tons of smelting debris have been uncovered on Slaves’ Hill, Ben-Yosef says, indicating industrial-scale production worthy of an ancient state or kingdom. Whether the Israelites or Edomites achieved such a level of development during the 10th century B.C. remains a hotly debated question, but Ben-Yosef is encouraged by the new finds, which were published in the Journal of Archaeological Science: Reports.