Built by Yves Le Denmat between 1703 and 1714, it replaces an older building, of which only the crypt remains. The crypt is in fact an ancient dolmen with a corridor, dating from the Neolithic period and serving as the floor of the south transept of the Chapelle des Sept-Saints. The six stones are divided into two granite tables supported by four vertical slabs. This dolmen is nothing more than the skeleton of an ancient tumulus, i.e. a grave covered in earth.