The structure is dated to the second half of the reign of Augustus (30 BC-14 AD), who had earlier founded the military colony Augusta Praetoria at an important road junction (24 BC). The Pont de Pierre was of particularly strategic importance, since in Aosta the transalpine routes to Gaul branched off into the Little St Bernard and the Great St Bernard Pass. In southeasterly direction towards the Po Valley, the road led over another segmental arch bridge, the excellently preserved Pont-Saint-Martin Bridge, located at the exit of the Aosta valley.