As part of the project to put up information panels in the archaeological area (2006) and prior to restoration work (2008-2009), a number of _sondages_ were dug with the aim of clarifying questions regarding the construction of two of the most important public buildings in _Libarna_, the theatre and amphitheatre. In the amphitheatre, trenches were dug in the underground spaces below the arena, in the sector of the seating embankments and outside the building. The investigations showed how the restorations undertaken from the 1930s onwards had reconstructed the walls by carefully following the line of the existing foundations, therefore keeping the plan of the structure intact and recognisable. Furthermore, some evidence, such as a hearth in association with a storage amphora, a floor surface and the loose make up for the external _platea_ floor, dated to the phase immediately before the amphitheatre’s construction. The finds indicate that the building site for its construction was set up during the 1st century A.D. Three _sondages_ were dug in correspondence with the walls supporting the _cavea_ and main entrance, revealing a section of the small channel which crossed it longitudinally. The most important evidence was the identification of a road make up on an east-west alignment, situated in the westernmost corner of the amphitheatre. Its alignment was completely different from that of the Roman city as it was following the changes to the urban plan carried out between the end of the 1st century B.C. and the 1st century A.D. The road, subsequently obliterated by a dump of earth functional to the urbanisation of the area, showed that the zone was already occupied in the period prior to the theatre’s construction, which is dated on the bases of its construction technique and by the pottery from the _sondage_ to around the mid 1st century A.D. Occupation of the _Libarna_ plain prior to the foundation of the Roman town was also documented in the stratigraphy by the presence, in the area of the amphitheatre and theatre, of residual proto-historic pottery, in particular forms attested in the Ligure III C phase.