During the Middle Ages, the region of Longemer was considered inhospitable and dangerous. In 1449, however, a small chapel was built on the shores of Lake Longemer by the canonesses of Remiremont. They wish to perpetuate the memory of Bilon. He was an officer of Duke Gerard of Alsace and became a hermit, residing from 1056 at a place known today as the Butte Bilon. Fallen into ruins, the chapel was rebuilt in 1727 and dedicated to Saint Florent by the Bishop of Strasbourg.