More than 30,000 large bronze coins dating back to the fourth century AD have been found by a member of the public during a dive off the coast of Sardinia, Italy—a discovery that could point to the presence of a shipwreck, according to the Italian culture ministry.
The diver spotted some “metal remains” in shallow water near the town of Arzachena, the ministry said in a statement Saturday. These turned out to be “follis”—Roman bronze or copper coins also later used as Byzantine currency.
Based on their weight, the total number of coins in the find is estimated to be between 30,000 and 50,000, the ministry said. This is more than the 22,888 follis hoard found in Seaton, United Kingdom in 2013, it added.
All the coins retrieved are in a “rare state of preservation,” with only four damaged yet still legible. According to the statement, the coins date from 324 to 340 CE and were produced by mints across the Roman empire.
“(The finding) highlights the richness and importance of the archaeological heritage that our seabed, traversed by men and goods since the earliest times, still guards and preserves,” Luigi La Rocca, director general of archaeology, fine arts and landscape for the region, said in the statement.
The culture ministry said the location where the coins were found—a sandy clearing between the beach and an area of seagrass—could, theoretically, preserve a shipwreck. Also found were walls of African- and eastern-produced amphorae—tall, narrow-necked Roman or Greek jugs with two handles.
“The treasure found in the waters of Arzachena represents one of the most important discoveries of numismatic finds in recent years,” La Rocca said, adding that the region has an “extraordinary heritage,” but that it is “also a very fragile one, constantly threatened by natural phenomena and human action.”
CNN’s Sharon Braithwaite contributed to this reporting.