The Croix-de-Bretagne fort was established between 1876 and 1879 at an altitude of 6,709 ft (2,045 m) southeast of Villar-Saint-Pancrace in the Hautes-Alpes department. It aimed at protecting Briançon from foreign incursions via the Montgenèvre pass and the Cerveyrette valley. In 1881, this long-range artillery work of the Séré de Rivières type accommodated 496 men and four horses and was armed with 12 guns and four mortars. It was designed to offer its occupants autonomy in food and ammunition for six months. Croix-de-Bretagne was one of Briançon's four high-altitude detached forts along with the forts of Infernet, Olive, and Gondran.