The thieves stole the coins numbering in the hundreds from the museum in Manching, Bavaria, during a nine-minute nighttime heist.

According to police, the thieves may have tampered with the museum’s alarm system, cutting internet cables just before breaking in, causing widespread outages.

Although the system managed to record the robbery, the thieves were able to go undetected until it was too late.

It was only the next morning that museum staff discovered that the coins were missing from their display case, the BBC reports.

Mourning the loss, Rupert Gebhard, head of collections at the State Archaeological Collection, said “it feels like losing an old friend”.