BERLIN (AP) — An amateur archaeologist who discovered several Roman silver coins in a field in western Germany realized he had stumbled upon something bigger when his metal detector kept beeping.

Oliver Riedl called the authorities for help and a group of experts who began digging immediately discovered a total of 934 Roman silver denarii. It is the biggest coin treasure ever found in Germany from the time of Roman Emperor Hadrian, the local office in charge of archaeological monuments said Tuesday.

The hoard of coins, which weighs 3.1 kilograms (6.8 pounds), went on display at the LVR-LandesMuseum Bonn on Tuesday.