During the excavation of the upper terrace of the “rocca” of Rione Terra, occupied by the so-called Temple of Augustus, the easternmost part of the forum of the ancient colony was uncovered, originally paved with rectangular marble slabs. The square was bordered to the south by a public building, perhaps razed in the early medieval period, on the same axis as the temple but at right angles to it. The orientation and its position on the south side of the forum suggest that this may have been the basilica, of which part of the marble architectural decorations survive, datable to a phase of the Flavian period. What remained of the building complex was the northern edge of the platform, built in squared tufa blocks faced with marble slabs and covered by an opus signinum floor decorated with marble chippings and partitioned on the north side by a continuous wall or a series of pilasters in opus mixtum. Amongst the marble fragments, found reused in the foundations of the modern building overlying the ancient one, were the hind quarters of a marble horse, a female head and a loricate headless statue. That this was probably Augustus was suggested by the presence on the cuirass of the figure of Jupiter Ammon flanked by two standing winged panthers.

Close to this building, on the south-west side of the forum was a large construction in opus mixtum, also originally paved with marble slabs of which the impressions left on the relative make up were visible. Exploration of this structure continues. The base of a marble semi-pilaster fixed with iron cramps was found at the centre of the east wall of this room that was perhaps part of another public building situated at the corner of the forum square.