This was the third and last campaign of excavations on the amphitheatre at Aquileia, during which trench 1 was extended towards the east and west to reach a total of 310 m2.
A comparison of the data from our excavations with the documentation from the 18th century excavations showed the amphitheatre was of the type defined as having a “hollow structure”: it measured 142 m along its major axis and 107 m across the minor one. The 2017 excavations completed the analysis of a module of the amphitheatre between two corridors leading to the area. This made it possible to reconstruct the entire plan of the monument, constituted (from exterior to interior) by a facade with 80 arches on pilasters, without an external gallery; a first ring of 80 radial sectors, which on the interior abutted an elliptical wall; an elliptical gallery below the cavea for movement of the public (1.80 m wide); a second ring of 64 radial sectors terminating at both extremities on pilasters; a second elliptical gallery (1.95 m wide), probably a service structure, and a podium around the area faced with stone slabs and with a crowning cornice. From the outside, the spectators could reach their seats by either going directly up to the higher parts of the cavea via the staircases in some of the wedges between the radials of the external sector, or by reaching the arena and the first rows of the seating tiers via 16 radial corridors passing under the cavea. It was also possible to reach the internal gallery via these corridors and from there climb the tiers using a system of stairways created in some of the wedges between the radials of the interior sector.

The 2017 campaign clarified the functioning of the drainage system, already partially hypothesised during past seasons. It was constituted by four elliptical drains (one at the foot of the exterior facade, two below the elliptical galleries, the fourth at the foot of the seating tiers) and by a series of other radials, situated below the corridors leading to the arena. Their sides and floor were brick-built and they were covered by stone slabs.

As regards the construction technique, two core samples, one taken in the area of the arena, the other in the area of the radials, showed that during the construction site phase the elliptical space to be used for gladiatorial games was isolated and the surrounding terrain was excavated to a depth of about three metres. The trench was then filled with stone blocks, mortar, and sand. The linear foundations, on which the elliptical walls and radials supporting the seating tiers rested, were then built on top of this make up. The radials of the inner ring were reinforced by walls consolidating the foundations, built in the spaces between them at both extremities, in order to avoid the possibility of differentiated subsidence that would have been ruinous for the structure.

A section of wall below the arena floor, cut by the drain at the foot of the seating tiers suggests that the area was probably occupied by dwellings prior to the construction of the amphitheatre, which were demolished to make way for the new building. The building materials accumulated below the arena floor were the result of this demolition and the charcoal from the core samples (to be dated by C14) will probably provide the chronology for the amphitheatre’s construction site phase, which a preliminary analysis dates to the mid 1st century A.D.