The Decumanus Maximus (what are now the Porta Pretoria, De Tillier and Aubert roads) linked the Porta Praetoria to the western exit of the Roman city: the Porta Decumana. From here the road that led to the Alpis Graia (hill of the Piccolo San Bernardo) commenced. With a double curtain and three passages flanked by towers, this doorway was re-adapted and remained in use throughout the middle ages and the modern age. It was known by the name Porta Friour, del Plot, di Saint-Genis, di Savoie and di Boczana, but the more frequent name was Vaudane (from Vaudagna = Valdigne).
The doorway lasted until 1812, the year in which it was demolished on the orders of the prefect of the Dora Department, in view of the restoration of the district and the widening of the road. The results of a series of excavation campaigns carried out in this area between 1988 and 1991, in compliance with the restoration of the former Hospice of Charity for the creation of the new Regional Library, allowed for the original physiognomy of the doorway to be outlined.
A considerable portion of the tower situated on the northern side of what is now Via Aubert still remains, the southern one, on the other hand, has been almost completely demolished down to the foundations. The digs brought a section of the paving of the decumanus maximus and part of a drain back to the surface.
The site cannot be visited at present.