A trio of French builders are expected to make bank after discovering a hidden stash of rare gold coins.

According to CNN, the workers came across the treasure back in 2019, while they were restoring a 13th century mansion located in in Plozévet, Brittany. The builders claim they found the first batch of coins inside a metal box lodged in one of the walls. Shortly after, they found a small pouch situated above a beam, and discovered it, too, was filled with coins.

“I thought it was a joke. But no!” property owner François Mion said. “As children, we all dream of finding hidden treasure. It was quite emotional.”

The 239 coins were eventually authenticated by the French Regional Preventative Archaeology Service. It was confirmed that the coins were minted between 1638 and 1692, during the reigns of Louis XIII and Louis XIV. Though their value will be determined at Deloys auction house later this month, CNN reports the stash has an estimated worth of up to $356,000.

The coins will be auctioned on Sept. 29, and the profit will be split in two ways: One half will go to Mion and his wife, and the other half will go to the three builders.

Mion purchased the mansion in 2012, which was likely built by an affluent family of farmers. CNN notes that the home’s area was known as a major trade region that experienced ups and downs throughout the 17th and 18th centuries.