Legend has it that Saint Bessus was a Roman soldier of the Theban legion following the emperor Maximian (3rd century AD), who called them to guard the northern slope of the Great San Bernardo to tame the rebellious local Celtic populations. However, since these proud soldiers did not agree to venerate the effigy of the emperor as if it were a god by professing their profound Christian faith, they were progressively condemned and persecuted. The survivors dispersed in various Alpine valleys, especially in Piedmont. San Besso and some of his companions managed to escape the massacre that took place in the Valais and, having separated, took refuge in the Valle Soana mountains, where they began a work of evangelization of the local "salassi" shepherds.
But the Emperor's soldiers managed to find him and killed him barbarically, throwing him from the top of the cliff of Monte Fantono. It is said that the saint, falling, left the figure of his body imprinted on the rock below.
Today, in that place, at 2,019 m above sea level, there is a sanctuary built close to that cliff and inside the church you can see the rock on which San Besso was martyred.
The route is difficult and demanding and, when the procession reaches the height of the large stone symbol of the saint, the faithful rotate around it before entering the small church; during the ritual the faithful carry out mysterious practices and rites, based on the belief that contact with the stone brings fertility, repeating more or less consciously ancient ritual practices dating back to pre-protohistoric times. It is customary, for example, to break off small flakes of rock to piously take home. It is a deeply felt tradition that deserves to be experienced.
The feast of San Besso is on August 10th, when hundreds of people come up from the valley and the Canavese plain below to reach the sanctuary. But the group that deserves the most praise is that of the faithful of Cogne led by the parish priest and the "conscripts", with the unmistakable scarf around their necks, who climb from the Cogne valley, overcoming the difficult Arietta mountain pass (2939 m) to devotion and in memory of an ancestral bond that binds the people of the two valleys. Tradition has it, not surprisingly, that the very first inhabitants of Cogne arrived from Val Soana.

From the square in Lillaz, in the municipality of Cogne, take route AV2 which continues into the Urtier valley. After reaching a group of houses and going past a short section of a penstock, it goes up into a wood, and after crossing a number of meadows, reaches the pasture of Goilles Inferiore. Next, the trail goes over the stream, across a small bridge, and continues on the orographic left bank, climbing up inside the wood. You then come to junction where the trees become less dense. Continue along the same itinerary, ignoring the path (13G) to the right that goes into Bardoney valley, until you come to the P.N.G.P. park guard’s lodge. Continue to further crossroads, where you ignore first route 13D on the right for Col Acque Rosse, then AV2 on the left for Col Finestra, and take routes 13B and 13C on the right. After a short section, take itinerary 13B, on the left at a junction, which takes first over grassy meadows and then along a hunting trail to the snowfield below the hill. The final climb is up a snowfield. Colle dell’Arietta is the most used pass between Cogne and Val Soana and is the pilgrim route to the Sanctuary of San Besso in the municipality of Campiglia.