The rarest of the coins is one of just five in existence, police said on Thursday. It dates back to the time of Emperor Constantino II, who was in power between 337 and 340.
In total, the Cultural Heritage police in Perugia, central Italy, confiscated 13 coins and various other "archaeological artefacts of interest" which dated back to the fourth century AD.
The owner has been charged with illegal possession of cultural objects and violation of the laws surrounding excavations.
Police also confiscated two portable metal detectors which they believed had been used to track down the artefacts in agricultural areas across the Umbria region.
Art crime is a huge problem in Italy, where artworks are stolen from unguarded churches and even from secure museums, and illegal excavations can uncover valuable historical treasures.
Over one million artworks are currently listed as missing or stolen.
Italy became the first country in the world to create a specialized police force to combat cultural crimes back in 1969. Its officers not only track down stolen treasures but have recently worked on securing and restoring the artworks threatened by the earthquakes in parts of Le Marche and Lazio last year.
To join the 'Art Squad', as it is known, officers first train as police officers (carabinieri) and then spend time training in art history, recognizing counterfeits, and restoring damaged works.
The Perugian unit is continuing its investigation into the coins found on Thursday, in order to determine if there are any other artefacts or further criminal charges applicable.
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Photo: Roman Clara/Bolzano Regional Government