An eight-year-old boy has unearthed an extremely rare silver coin while playing in a sandbox, dating to about 1,800 years before he was born.

The young boy, who was identified only by his first name, Bjarne, was playing in a sandbox at his primary school in Germany when he made the incredible discovery.

He rushed home to show the treasure to his family in Bremen, a city in northern Germany, upon finding it in August 2022.

Bjarne’s parents contacted authorities and archaeologists confirmed the coin was minted during the reign of the Roman Empire.

The coin was identified as a Roman denarius minted during the reign of Emperor Marcus Aurelius Antoninus, who held the throne from A.D. 161 to 180, according to a translated statement released on August 11.

The heavily worn coin, which weighs 2.4 grams, was minted during a “time of coin deterioration” when the Roman Empire decreased the silver content in its currency as a direct result of inflation, Uta Halle, the state archaeologist, said.

Halle called the find “something very special,” since it’s one of the few times a denarius has been discovered in Bremen.

Bremen, unlike many parts of Germany, was never under Roman rule. It was inhabited by the Chauci, an ancient Germanic tribe that often traded with ancient Romans, which could explain how the coin wound up buried in the soil, according to The History Blog.

Bjarne won’t be able to keep the lucky coin, as such finds belong to the state, per the Bremen Monument Protection Act.

Still, state archaeologists praised him for his “alertness and curiosity” and plan to give him two archaeology books as a reward, according to the statement.

Halle said she hopes the denarius finds a home at the Focke Museum in Bremen, where she heads the department of prehistory and early history.