A new excavation campaign in the Forum of Caesar involved two distinct sectors (A and B) in the south-eastern area of the square.

In sector B, at circa 1 m below the forum’s pavement, the eastern side of a square building came to light. Built in blocks of capellaccio, the construction technique and comparison with analogous structures date it to between the 6th-5th century B.C. A circular well was associated with the structure.

The building was destroyed by a great fire, evidence of which was seen along the entire stretch of the perimeter that was uncovered, and which also appeared in other sectors of the excavation. On the basis of the stratigraphic sequence and the pottery recovered, generically datable to between the late 5th and the high 4th century B.C., it cannot be excluded that these are the remains of the Gallic fire of 390 B.C. To date it has been difficult to find evidence in the city of this traumatic event.

This episode was followed by a substantial phase of reclamation in the area, which was filled in order to create a new level. New structures were built here in opus quadratum datable to sometime after the mid 4th century B.C.

In sector E the excavation defined the layout of the first Forum of Caesar, which was circa 20 m smaller (c. 140 × 75 m) with respect to the final version (c. 160 × 75 m) inaugurated by Augustus in 29 B.C. During the last excavation campaign three rectilinear foundations were uncovered. They ran parallel to each other on a north-east/south-west alignment and belonged to the short eastern side of this first forum. Furthermore, it was possible to check the width of the intercolumniation (2.80 m) of the forum’s internal colonnade and it was discovered that the short side of the forum must have had a double portico screened to the rear by an order of inward facing columns or pilasters. This first forum was probably the one which Julius Caesar inaugurated in 46 B.C.

The discovery of a conduit dating to the early Augustan period, created by cutting the preceding foundations of the forum’s first short side, provided proof that during this period the square was extended in the direction of the Argiletum.