The is no summary for this season.This was a campaign of explorative excavations aimed at assessing the state of preservation of the amphitheatre walls, but also the depth of earth covering them and assessing the difficulties inherent in any future open-area excavation. In effect, the eastern part of the amphitheatre had been the object of a series of investigations between the 1700s and the 1940s, but none of its structures had been identified on the land belonging to Palazzo Brunner, which is therefore an area of interest., The amphitheatre’s approximate overall dimensions (c. 148 m on the longest axis, and 112 m on the shorter one) and its position within the Roman town are known thanks to earlier archaeological interventions, however numerous architectural-structural aspects and the chronology remained to be clarified. Based on the results of the preliminary geophysical survey, two trenches were opened (9 x 5 and 17 x 5 m), which confirmed some of the conclusions relating to the monument’s construction, but also revealed some new information. Although the amphitheatre was heavily robbed over the centuries, the excavations exposed a substantial and to date unknown foundation platform, almost 4 m wide, which must have supported a series of pillars on the exterior of the facade. This is of significance, as it constitutes evidence for the presence of an external gallery, therefore indicating that the amphitheatre was larger than previously suggested. In addition, the excavations uncovered the robber trench of one of the pillars of the internal gallery, already documented in the eastern sector by the 19th century excavations, and one of the radial walls that supported the seating tiers, preserved at foundation level. These structures stood on a massive consolidating make up of packed cobbles and stones solidly embedded in the terrain at several levels. The differences in technique and level between this foundation structure and that of the external gallery suggest the amphitheatre was built in two phases with a later extension. Although the dating for the construction phases and its abandonment remain to be clarified, it is already possible to suggest that the external gallery was demolished in about the 3rd century A.D. when the late antique city wall was built. Its line ran at only a few meters from the amphitheatre and its substantial inner earthworks have been identified in the excavation area. Although lacking part of the seating tiers, the amphitheatre must have continued to be used in this period. In fact, it went out of use in the late antique-early medieval period, when the modest dwellings were built inside it, reusing the surviving ancient walls. Occupation layers and hearths attest the presence of these dwellings.

In 2016, the trench opened in 2015 was extended to the north and this completed the excavations of an entire section of the amphitheatre, from the external floor level to the arena, documenting its architectural typology and construction techniques. In 2015, only the foundations and robber trenches were uncovered, this season the excavations showed that in some sectors of the building the structures were very well-preserved, standing up to 1.70 m high. To date the structures brought to light at a maximum depth of 3.17 m below ground level (0.28 m a.s.l.) are, from the exterior to the interior: - A 6.90 m wide sector of a_ platea_ that continued beyond the trench edge. This was probably the paving outside the amphitheatre and not the foundation of an external gallery as suggested in 2015: therefore, the amphitheatre did not have an external gallery and its dimensions can be reconstructed as about 142 x 107 m; - a complete radial wall from the external radian and parts of a further three, built in _opus_ _caementicium_ faced with small limestone blocks and attested to the north of an elliptical wall. The complete radial wall was 10.20 m long and 0.80 m wide and was situated south of a robbed-out pillar. The upper surfaces of the walls presented clear traces of the _sesquipedales_ that were originally set in mortar and later removed, evidence that constructions in _opus_ _listatum_ had tile courses. The distance between the walls was not regular: in two of the spaces between them there were two _opus_ _caementicium_ structures, which probably served to support the stairs leading up the _cavaea_; - the elliptical wall to which the external ends of the radial walls joined to the south, uncovered for a length of 10.70 m and to a height of 1.70 m, characterised by a very well-finished facing of small limestone blocks with regular mortar stilatura grouting; - the two walls belonging to the inner radian of radials, heavily cut to the south and north (where there was evidence of two pillars) by robbing. Between these walls, there was also an _opus_ _caementicium_ structure that supported a staircase. These structures show that the amphitheatre of Aquilea was a “hollow structure”, disproving the hypothesis sustained in the past that the arena had been excavated into the terrain; - a section of the elliptical podium foundation, 2.15 m wide and built in _opus_ _caementicium_; - a section of a 0.50 m wide elliptical wall built in stone blocks, which delimited the arena space and perhaps constituted the northern parapet of a drainage channel that must have run at the foot of the podium to collect rainwater running off from the seating tiers, - a limited area of the arena whose floor seemed to be constituted by a sandy-clay layer, below which a layer of building materials emerged, mainly constituted by painted plaster fragments and two _sesquipedales_ aligned east-west, whose significance will be clarified during future investigations. In fact, the excavation of this layer could provide useful material for dating the structure, particularly as dating was compromised in other sectors by the impossibility of reading the construction site phases due to a rise in the water table. From a technical point of view, this year’s excavations also confirmed that the wall foundations were constituted by a substantial make up traced on the terrain prior to the construction, which laid out the lines of the radial and elliptical walls. From a diachronic point of view, it was seen that some sectors of the amphitheatre were reused in the late antique-medieval period for dwellings, which exploited the standing ancient walls. The open space of the arena was reused for agricultural purposes.

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.