In 1900, archaeologist Paul du Chatellier found a pedrisco while digging in the necropolis of the area. The engraving was extracted from the tumulus and exhibited in the small museum it had in the castle of Kernuz (Pont-L’Abbé). They aroused Chatellier's curiosity, but did not know how to interpret them: “It’s hard to describe this curious monument full of cups, circles and images. Let us not be fooled by fantasy, let a Champolion that may show up one day read it on our own.”

In 1911, with the death of Chatellier, the family sold the entire collection (including the slab of Saint-Bélec) to the National Archaeological Museum of Saint-Germain-en-Laye. In the museum winery the slab was forgotten throughout the century, until it was rediscovered in 2014. Archeologists Yvan Pailler of the University of West Brittany and Clément Nicolas of the University of Bournemouth have been in charge of investigating the object. They have digitized the stone and analyzed in detail all the marks and changes made by man. For line reasons, they thought from the very beginning that it could have been a map. Then they saw that these cartographed precursors also modified the natural relief of the stone to represent the orography of a real area. So Saint-Bélec would be a three-dimensional map.

Finally, they have also come to the conclusion of which particular area of Brittany is on the map: 13 kilometres from the Odet River valley. In the rock you can identify the hills of Coadri, the Black Mountains and the massif of Landulan, the lines indicate the river network and some brands coincide with the remains of buildings, tumules or roads of the Bronze Age. Geolocation has concluded that the map represents the area with an accuracy of 80%. Several similar pieces have been found in the world, but so far it has not been possible to know the relief that these other maps represent. According to Clément Nicolas, “it can be the oldest map of an identified territory.”

Archaeologists don't know why the map was made, or why it was buried in a grave. Perhaps the authorities in that territory commissioned the work every time we had the territory, and when a lineage chief died, they decided to bury him with him. Or maybe the artist who engraved the stone burial along with his work. Clément Nicolas has one clear thing: “We tend to underestimate the geographic knowledge of societies of the past.”