In the depths off the northeastern shores of Sardinia, a diver’s discovery of something glinting in the sunlight has led to a remarkable underwater treasure trove.

Italy’s culture ministry announced on Saturday that tens of thousands of ancient bronze coins dating from the first half of the fourth century were found nestled in the seagrᴀss, a stone’s throw away from the Mediterranean island’s coast near the town of Arzachena.

Shipwreck Spoils?

The ministry has kept the timeline of the discovery discreet, mentioning only that the first sight of metal by the unnamed diver spurred a full-scale archaeological investigation. Under the guidance of Italy’s art protection squad and the ministry’s undersea archaeology department, the seabed revealed its secrets—a vast spread of coins mainly across a sandy expanse between the seagrᴀss and the beach. This area, intriguingly shaped and positioned, hints at the possibility of a shipwreck’s remnants lingering nearby.

The hoard of coins in situ on the seabed. Credit: Italy’s Culture Ministry.

Numismatic Wonder

The Culture Ministry detailed that the coins, identified as follis, number between 30,000 to 50,000—a find more substantial than the 2013 discovery of 22,888 coins in Seaton, UK.

The coins, alongside walls of amphorae from African and Oriental production, were first noticed by a local diving enthusiast. The following day, a combined effort from several units including the Superintendency of Archaeology, the Carabinieri of the Cultural Heritage Protection Unit, and the Underwater Unit of the Carabinieri in Sardinia, with support from state and local authorities, confirmed the find.

Exceptional Preservation

Almost all the coins retrieved are in an extraordinary state of preservation, with only four pieces showing damage but still legible. The span of their minting dates from 324 AD (starting with Licinius’ coinage) to before 346 AD—the absence of centenionales, which began minting at that time, solidifies their age. The coins have been traced back to nearly all the empire’s mints active in that period, with a few notable exceptions.

The ancient coins are in an exceptional state of preservation. Credit: Italy’s Culture Ministry.

An Archaeological Boon

The preservation and analysis of these coins promise to unlock deeper insights into the historical context of the find. Luigi La Rocca, ABAP General Director, expressed the discovery’s significance: “The treasure found in the waters of Arzachena represents one of the most important discoveries of numismatic finds in recent years.”