A mysterious cipher carved into stone some 230 years ago in the village of Plougastel-Daoulas in Brittany, France has finally been solved.

The riddle, discovered three decades ago and visible only at low tide on a three-foot-tall slab, is composed of 20 lines of text written in an unknown language. Some indiscernible highlights, according to the BBC, include phrases like: "ROC AR B... DRE AR GRIO SE EVELOH AR VIRIONES BAOAVEL... R I OBBIIE: BRISBVILAR... FROIK...AL."

Drawings of objects, such as a sailboat and heart-topped cross, are also inscribed, as are the dates 1786 and 1787.

drawing of a boat is one memorable detail on a rock in Plougastel-Daoulas
A drawing of a boat is one memorable detail on the famous rock. (Photo: FRED TANNEAU/Contributor/Getty Images)

With local archaeologists and scholars stumped as to the meaning behind the message, town officials decided to create a contest with a 2,000 euros ($2,200 USD) prize for anyone who could come up with a plausible translation.

"We thought maybe out there in the world there are people who’ve got the kind of expert knowledge that we need," Dominique Cap, mayor of Plougastel, told the BBC. "Rather than stay in ignorance, we said let's launch a competition."

While clues to aide potential interpreters were sparse, local officials did recognize some letters and words as coming from a mix of 18th-century Breton, French and Scandinavian. Some letters were also upside-down and reversed, leading to some speculation that the author may have been semi-literate.

inscription on a rock in Plougastel-Daaoulas, western France
What does this inscription mean? (Photo: FRED TANNEAU/Contributor/Getty Images)

According to The Jerusalem Post, 61 translations were submitted in late 2019 from around the world. In the end, the judges settled on two winners to split the prize, each coming to the conclusion that the riddle in stone was something of a memorial to a solider named "Serge Le Bris." The inscription itself appears signed by another solider named Grégoire Haloteau and dated May 8, 1786.

The first winning translation, from English professor and Celtic language expert Noël René Toudic, reads in part: "Serge died when, with no skill at rowing, his boat was tipped over by the wind."

The second, from historian Roger Faligot and artist Alain Robet, features a more sinister interpretation. It reads: "He was the incarnation of courage and joie de vivre. Somewhere on the island he was struck and he is dead."

Frenchmen Robert Faligot (right) and Noel Rene Toudic seen near the inscripted rock they unscrambled in Plougastel-Daaoulas
Frenchmen Robert Faligot (right) and Noel Rene Toudic seen near the inscripted rock they unscrambled. (Photo: FRED TANNEAU/Contributor/Getty Images)

Despite the best efforts of the winners, Cap told Agence France-Presse that several lines of text remain undeciphered. Officials are also eager to learn more about the two men referenced in the stone, who may have been part of a fort that once existed in the town.

"There is still a long way to go to completely lift the mystery," he added.

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.