The massive octagonal sanctuary of the Temple de Mars

The Temple de Mars is the vestige of a Romano-Celtic fanum and its courtyard, located in Corseul in the department of Côtes-d'Armor, France. Probably built around the middle of the 1st century CE, the sanctuary was used until the end of the 3rd century. While it is traditionally referred to as the temple of Mars, there is no decisive evidence to confirm this specific attribution to the cult of Mars.

The site featured an octagonal cella, where the cella originally held a statue of a deity. Pilgrims would have walked in procession around this sacred chamber. The sanctuary was a significant structure, with a total size of approximately 90 by 80 meters. This made it one of the largest sanctuaries in all of Gaul, with the grounds altogether covering almost one hectare.

Today, the temple retains only three sections of walls approximately ten meters high. At the southeast corner of the site stands the Haut-Bécherel farm, built in the 16th century. This farm rests on the foundations of the south gallery of the sanctuary, with walls made of cut and rubble granite as well as shale rubble. The site was classified as a monument historique in 1840, and the Gallo-Roman site received a similar classification in 1997.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons