The fort's construction, in order to obtain a secure barrier of the valley, was probably suggested and directed by Engineer Guy de Creuzet de Richerand. The pentagonal plan work was defended on four sides by a moat, the fifth was naturally protected by an inaccessible slope. Three raveliners protected as many curtains while a bonetto defended the upper rampart, the Roudour bastion. Inside were the logistical buildings arranged around a central parade ground, such as the Government building, the chapel, the lodgings for the officers and the troops, the powder magazines and warehouses.
Having fallen into Savoy's hands after the siege of 1708, and finally annexed with the whole valley after the treaty of Utrecht, Mutin continued to remain in service, becoming part of the defensive system and constructed together with the fortified district of Fenestrelle, on the opposite side of the valley.
During the nineteenth century the lack of defensive efficiency, the deterioration of the structures and the decision to erect the valley road downstream the Ridotta (Redoubt) Carlo Alberto determined the abandonment of Mutin, which was partially demolished along with the mines.
