ROME (AP) — Italian authorities are unveiling the "epochal" discovery of hundreds of Roman-era gold coins that were found during excavations to build a new apartment building in northern Italy.

Construction crews digging in the historic center of Como discovered the small stone jar containing about 300 coins last week.

Culture Minister Alberto Bonisoli joined archaeologists and the carabinieri art squad on Monday to unveil the first 27 coins after they had been catalogued.

Bonisoli said the coins, believed to date from 474 B.C., were extraordinary but still not fully understood, primarily because the jar holding them is unusual compared to other Roman-era amphorae that were common containers at the time.

He told a press conference: "More than exceptional it's epochal, one of those discoveries that marks the course of history."