The first construction of a rampart at Forum Iulii dates back to the Augustan period (27 BC 14 BC). But there were several phases of construction at different times.
The Roman wall (listed as a Historic Monument in 1886) was built in a small regular sandstone blocks from the Esterel Massif. It enclosed an area of approximately 35 hectares. This monumental wall, 8 m high, 2.50 m wide, was pierced with 4 gateways corresponding to the ends of the cardo (north-south axis) and decumanus (east-west axis), of the Roman city and was around 4 km long.
Two gateways have survived to this day – the Porte de Rome to the east and the Porte de Gaule to the west. The Agachon gateway to the north was destroyed in 1955. To the south a wide inclined slope ran down to the port, located below, and the Porte d’Orée which is not a gateway to the city but part of the 2nd century baths. These are contemporary names, the gateways originally took the name of the nearest city to Forum lulii: the gate to the west was then called Aquae Sextiae (Aix en Provence) and to the east Antipolis (Antibes). They could also take the name of the Roman road that passed underneath, here the Via Aurelia, which left Rome and crossed Fréjus.
The top of the rampart, in the 700 m long north-east section, served as a foundation for the aqueduct bringing water from Mons to the city in the second half of the 1st century.
The wall was punctuated by several regularly spaced circular towers, the remains of which can still be seen. The outer facade of a single tower is still preserved, giving an idea of the original height.
West of Butte Saint-Antoine, it disappears in places, revealing empty semi-circular alcoves that served as internal buttresses to support the embankment of the hill, a technique also found in Nîmes and Pompeii.
With a fairly regular route and used partly as an aqueduct, the purely military role of such a wall would not seem to be primordial. It was more a question of demonstrating to visitors the prestige of the city and demonstrate the extent of the pomerium, the sacred limit of the city according to the legendary creation of Rome, which refers back to the legend of Romulus and Remus.