How a rock from the Bronze Age was used by researchers as a "treasure map"

The Saint-Belec slab, a piece of rock with mysterious markings that lay largely unstudied for 4,000 years, is now being hailed as a "treasure map" for archaeologists in north-western France. This ancient map, discovered in 1900 but not recognized for its significance until 2014, has sparked considerable interest among researchers.

The Saint-Belec slab is considered Europe's oldest map, and researchers have been working to decipher its markings to help them date the slab and rediscover lost monuments. The map covers an area of roughly 30 by 21 kilometers. To find archaeological sites, the team plans to survey this entire territory and cross-reference the markings on the slab with contemporary maps. This process could take up to 15 years.

Archaeologists have spent the past few weeks digging at the site where the slab was initially uncovered / © AFP

The slab is covered in engraved symbols, some of which immediately made sense to the researchers, representing rivers and mountains in the Roudouallec region of Brittany. These maps matched current maps with an 80% accuracy rate. However, they still need to identify all the geometric symbols and legends associated with them.

The slab also features small hollows, which are believed to indicate burial mounds, dwellings, or geological deposits. Deciphering the meaning of these symbols could potentially lead to many new discoveries.

The so-called Saint-Belec slab was claimed as Europe's oldest map by researchers in 2021 / © Archives departementales du Finistere/AFP/File

In recent weeks, the archaeologists have been conducting excavations at the site where the slab was initially found, which is believed to be one of the largest Bronze Age burial sites in Brittany. This dig has already yielded previously undiscovered fragments of the slab, suggesting that it had been broken into pieces and used as a tomb wall. This use of the slab as building material may signify shifting power dynamics in Bronze Age settlements, possibly indicating a kingdom's collapse due to revolts and rebellions.