The Celts in Piedmont?

It seems so! Along the road to Briançon ( Brigantium ) the Roman historians tell of a place called " Excir-gomagus" that was probably a village of Celtic origin. But the wonder that strikes the traveller is a wall, that can be seen from kilometres away high on the mountain, along the road that goes from Turin to Susa. The valley is closed by a castrum with two orders of fortifications that were already documented in 1300. Two centuries later it was adapted to firearms, and it stopped the Swiss infantry. Taken by the Huguenots during the religious wars, it was reconquered by the Catholic army of the valley.  The history of the stronghold is full of important events: conquered by Carlo Emanuele I, then lost, it was taken by the French in 1595. Few people know that in 1600, in the dungeons of the stronghold a mysterious prisoner was held in custody: the Iron Mask.At the beginning of the XVIII century it was in possession of the Savoia.
 
The defences built by the French were directed towards the upper valley and fortified with 45 guns, that had resisted against the same enemy over the centuries. It was reconstructed in two stages in 1800 and it was only abandoned in 1915 when the 22 breech-loading guns were dismantled. In the XVIII century the fortification system of the Susa Valley was centred on the fortresses of Exilles and of Susa. The fort point of Brunetta of had a different destiny: its imposing structure, endowed with inexpugnable ramparts cut into the rock had been built by the Savoia in 1708. They had more than a hundred guns, with four gigantic cannons which were never used. The stronghold, in fact, was never tested and it was dismantled by Napoleon with the "peace of Paris".After the tunnel of Mompantero the Autofrejus develops at the feet of its imposing ruins, hidden by the self-sown vegetation that has covered the hill.