The archaeological investigation covered an area of circa two hectares and examined the Mausoleum of Augustus, the immediately surrounding area and, to a certain width and depth, the area beyond. The investigations were undertaken due to the necessity of determining the feasibility of a project to modernise the whole of piazza Augusto Imperatore. The trenches opened in the circle surrounding the mausoleum revealed, at between 30 and 40 metres to the east and west of the entrance to the tomb, the position of the _opus caementicium_ foundations of two obelisks which in antiquity flanked the monument. The obelisk situated to the east still preserved part of the core of its base. In the central zone the modern flight of steps which provided access to the area was demolished and an intermediate level of graves and “a cappuccina” tombs, the post abandonment levels and further ancient levels were removed. This exposed a stretch of paving in travertine slabs, positioned at a level of 10.58 m a.s.l., which can be linked to the large stretch of paving situated on the side of the access stair way and discovered in the 1950s; this was already visible before the beginning of the excavations. The investigations in the southern sector of the area revealed the remains of the ground floor and basement levels of the Renaissance building which housed the ‘Collegio dei Croati’ which was demolished between 1934 and 1936. The demolition of the buildings revealed Renaissance structures in direct contact with Roman levels and, in particular, with an ancient surface formed of carefully worked travertine blocks and a cement foundation. The presence of the foundation, of lines and crosses incised on the blocks suggests the existence of standing structures that have not survived. North of the mausoleum between via di Ripetta and via dei Pontefici the excavation of the remains of Palazzo Sonderini exposed, in continuity with the Renaissance structures, walls belonging to a building of 1st-2nd century date, the so-called _domus_ del _curator Augusti_. The investigations on the monument undertaken by Colini in 1925-26 and again in 1936-39 were anything but exhaustive, and thus the cavities and trenches dug at that time were reopened and the investigation extended to the entire research area. In particular the investigations inside the mausoleum looked at the annular ambulatories around the cella revealing the foundations of the walls in travertine blocks and the collapse of the annular vaults covering the ambulatories which were also entirely built in blocks. Of the _opus reticulatum_ substructures between the third and fifth ring, not practicable in antiquity, the first of the semicircular concamerations to the east of the _dromos_ was partially excavated. A complete investigation was made of the eastern sector of the second concameration where the original Augustan fill was seen to reach the Renaissance level of reuse of the area. The investigation has shown that the _opus reticulatum_ walls were built without scaffolding but by creating a series of platforms by dumping earth inside the concamerations.

In May-October 2010 the Rome Superintendency renewed excavations, begun in September 2007, in the area of Piazza Augusto Imperatore with the aim of acquiring new data of use in the planning of the modernisation of the piazza. The excavation looked at the sector occupied by the remains of the Oratory of San Rocco which had been demolished in the 1930s. The first phase of work saw the removal of several overlying floor levels, dating to different phases of the oratory’s life and demolition of the surviving foundation structures. The Renaissance floors sealed a series of deposits obliterating the Roman levels and nine burials were found within them. Only four of the burials showed the use of large tile fragments and amphora walls, the other were in simple earth graves. This group of burials was part of the already known late antique necropolis of the Mausoleum of Augustus, mainly excavated without documentation in the 1950s, the graves being concentrated in a limited area, on axis with the front of the mausoleum. A preliminary analysis of the materials from the layers cut by the graves produced nothing earlier than the end of the 4th-beginning of the 5th century A.D. and thus a terminus ante quem non for the dating of the cemetery. The removal of the dumps completely exposed a structure on an east-west alignment, constituted by reused blocks of travertine and marble, positioned directly upon a Roman paved surface. A number of blocks decorated with bay tree branches in relief were also reused in this structure, largely visible at the end of the previous campaign. Immediately south of the latter, and parallel to it, was a partially preserved structure constituted by smaller and more irregular marble and travertine fragments, positioned up against the terrain probably to function as a containing structure. Below the structures described a new, large area of travertine paving came to light, dating to the Imperial period, situated at 10.58 m a.s.l., and connecting to the part uncovered in the 1950s and that which emerged during the 2008-2009 investigations. On the opposite side, a small trench opened to the east revealed another patch of paving corresponding to the eastern limit of the paving in front of the mausoleum. Moreover, a longer section of the Roman sewer, on an east-west alignment and delimiting the paved area to the south, was investigated. This structure, known in the modern era as the Chiavica di Schiavonia, had been seen and documented by Baldassare Peruzzi when the church of San Rocco was built. The demolition of the structures belonging to the block between via degli Schiavoni and vicolo del Grottino was extended to the west, and this revealed the conglomerate foundations of the structure in travertine blocks, discovered in 2008-2009 to the south of the ancient sewer. In the eastern sector of the piazza the demolition of the foundations belonging to the block owned by the Croatian College also continued. The structures were removed down to the level of 12 m a.s.l. as foreseen by the modernisation project. The Renaissance levels sealed the remains of late antique buildings with mosaic floors. The greater part of these structures continued beyond the excavation area; thus they are of difficult interpretation. In the same sector a series of progressive rises in the ground level of the area were identified, formed by dumps with related floor levels; all of this stratigraphy can be attributed to the Roman Imperial period.

Nel mese di ottobre, con il supporto dei tecnici dell’Associazione Roma Sotterranea, è stata intrapresa l’esplorazione di un tratto antico del Chiavicone di Schiavonia, al fine di individuare la sua connessione con il sistema drenante del Mausoleo. Sembrerebbe, infatti, per quanto è stato possibile vedere, che in esso convergesse almeno un condotto trasversale proveniente dal monumento. La fogna è posta al margine del lastricato di travertino antistante al Mausoleo, in una posizione che corrisponde al salto di quota tra l'area in cui sorgeva il monumento e l’area del Campo Marzio a sud di esso. Il dislivello di oltre 60 centimetri era colmato da una gradinata, di cui è riconoscibile l'impronta sul lastricato. Lo scavo parziale del condotto, effettuato in corrispondenza di due pozzi di immissione non originari, è stato reso difficoltoso dall'afflusso costante di acqua, probabilmente di falda, e dalla presenza di un notevole interro. È stato comunque possibile verificare che il canale, realizzato in conglomerato cementizio, è largo internamente m. 0.75 e ha copertura a doppio spiovente. Sarà necessario riprendere con altri mezzi l’indagine per definire meglio le caratteristiche costruttive del manufatto e per ricostruire, se possibile, il sistema di raccolta delle acque provenienti dal Mausoleo, verosimilmente drenate attraverso diversi condotti variamente dislocati e convogliate in questo collettore che si gettava nel Tevere. Sono altresì proseguite le operazioni di rilievo archeologico degli elevati e dei conci di travertino crollati dalle volte del monumento, realizzate dalla Società Pragma s.r.l. e coordinate dal gruppo di ricerca della Sovraintendenza Capitolina.