A group of Italian divers discovered a Roman shipwreck stocked with hundreds of ancient clay jars in the warm waters off the coast of Sicily, authorities said.

The ship is believed to date back to the second or first century B.C., according to the Italian Ministry of Culture. Divers located it about 3 miles off the coast of Mazara del Vallo, a city on the western coast of Sicily.

Alessandro Giuli, Italy’s minister of culture, described it as “one of the most important underwater archaeological discoveries of recent years.”

Videos posted online by the Ministry of Culture show divers swimming over hundreds of amphorae, clay jars used in ancient Greek and Roman societies to store goods like wine and olive oil.

Fisherman Giacomo De Mola said in an Instagram post that he and other divers were using sonar technology to survey the seafloor off the coast of Sicily when they came across “what looked like an ordinary rock.”

He said something compelled him to get a closer look. At first, he thought the large mass was what he’d assumed: another big rock. But as he moved closer, an immense pile of ancient clay jars came into view.

“It is hard to describe the feeling of being among the first humans in nearly 20 centuries to see that place again,” De Mola said.

The divers reported the discovery to the Sicilian Region’s Superintendency of the Sea, a public body that oversees the identification and management of marine archeological sites off the island’s coastal waters. An initial analysis found that the pile of amphorae is about 70 feet long, 20 feet wide and over 6 feet tall.

“This is, without a doubt, the most incredible discovery of my life,” De Mola said.