When his metal detector spotted the first coin, Oliver Riedl knew he had uncovered something special; removing the surrounding earth revealed a small, rounded piece of silver—obviously ancient—that had likely remained hidden here for centuries.
The coin, an example of Roman denarii, isn’t necessarily an uncommon find in parts of Europe that once formed the greater Roman Empire, but they are still highly sought after by collectors. Had it been the only object Riedl uncovered that day, it still would have made his outing worthwhile.
But then, his metal detector began beeping again.
Soon, another coin was uncovered, then another. And then another. And another.
Riedl, an authorized metal detectorist legally searching for such ancient artifacts, had already found 15 Roman denarii in the field near Wesseling, south of Cologne, where his searching that day began. But his metal detector continued to beep as it registered more hits nearby.
How many more of these ancient coins might there be? Rather than continuing to dig, Reidl, now suspecting a much more significant find, decided to contact archaeologists.
He was right. Once archaeologists with Germany’s LVR Office for Archaeological Heritage Management arrived and investigated the site, they uncovered more than 934 denarii, a hoard totaling close to seven pounds of ancient Roman coinage.
The 1,900-year-old collection of artifacts, which dates to the reign of Roman Emperor Hadrian, is now believed to be the largest known coin hoard from the period ever found in Germany, and the fifth-largest from the period known from anywhere else in the world.
Not Just Another Coin Hoard
The ancient hoard was likely intentionally buried, and archaeologists believe they may have been placed in the ground sometime around A.D. 125. Still, the contents of the hoard reveal something more complex.
The oldest coins in the batch are centuries older, dating to 148 B.C., which places them during the Roman Republic. Those coins would have therefore circulated for more than 270 years before becoming buried alongside the much later denarii accompanying them, revealing an ancient collection of historic coins separated by almost three centuries across the timeline of the ancient Roman world.
The majority of the silver pieces were coins minted under the Flavian emperors sometime between A.D. 69 and 96, which suggests that the hoard was likely assembled around A.D. 100, and then hidden in the field decades later.
Among the obvious lingering questions about the discovery is who buried the hoard, and why they never returned for it. Similar unrecovered hoards have remained a subject of interest to researchers for centuries, and academic research in recent years has examined the phenomenon, attempting to understand why many of these collections of wealth remained hidden in the ground for centuries or even thousands of years.
Although the discovery was made within an area that once formed part of Rome’s heavily militarized frontier, there is no evidence that currently links it to soldiers or military activity.
Still, the hoard’s contents and its value do offer some perspective on the wealth its mysterious owner possessed. By contrast, a Roman legionary would have earned only around 300 denarii every year at the time the hoard is believed to have been placed in the ground. A hoard the likes of what Riedl uncovered in Germany would have comprised close to six years of those earnings.
What remains is an ancient treasure from the Roman world that remains a mystery, even after a metal detectorist’s chance discovery helped bring it into the light after remaining hidden for almost two millennia.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.