THE ADDED VALUE OF METRO C: THE ARCHAEOLOGY
The construction of the metropolitan Line C of Rome, which crosses a vast area from urban suburbs to major sectors of the historical centre and the central archaeological area, is an exceptional archaeological resource rather than an interference with the work to be done.
The construction of the stations requires the removal of substantial volumes of buried archaeological objects. This provides a unique and hitherto unseen opportunity to acquire new and important historical data, even in areas so far little known archaeologically, or not even known at all. This is largely due to the depth of the layered ancient stratigraphy of the ground which in some cases reaches 20 metres in depth from the contemporary surface.
The necessity of having to operate in a territory that presents a considerable density of archaeological findings within a multi-layered urban fabric rich in monumental remains and historical buildings, has meant that an intricate process of collaboration between the Archaeological Superintendent and those responsible for the construction of the infrastructure has grown from the project of the C Line. This has led to a definitive broad investigation programme which is divided into two phases: the First Phase and the Second Phase Investigations.
The collaboration between engineers and archaeologists began with the municipal administration technicians before the project (then based only on the tender) went ahead. This collaboration led to the exclusion of some areas to be built on where significant archaeology was already present. For example the Stazione Lodi was originally planned in Piazza Lodi, but because the remains of the Circo Variano lie beneath the piazza it was moved to the Via La Spezia where it was able to be built due to the remains of an ancient ‘tufa’ quarry.
In some cases it was the Archaeological Superintendent of Rome who suggested the most suitable locations for a station, as happened with the Stazione Fori Imperiali, now under construction in the area of the hills of the Velia which were built over in the 30s to build the road of the same name.
After the international competition which granted the construction of the project, the development of the final and executive planning of the T2, T3, T6 and T7 sections began in 2006. The First Phase of the archaeological investigations took place in various different ways:
- coring recoveries with archaeological interpretations
- small archaeological inspections with self-sinking shutters to protect the site
- larger archaeological excavations supported by reinforced concrete piles or diaphragms to keep the surrounding protective fences from collapse
In the central area alone, along the T3 section from Via Sannio to Piazza Venezia, and along the T2 section from Piazza Venezia to Clodio/Mazzini, 22 archaeological sites have been opened for the First Phase initial investigations, some of which have provided significant results. Three other sites have been explored along the T6 section (Giardinetti, Torre Spaccata and Giglioli stations).
The two exploratory trenches dug for the design of the Stazione Fori Imperiali on the corner of Via delle Carine and the Via dei Fori Imperiali, have provided documentation of the construction, use and restoration of a stretch of the ancient Vicus ad Carinas, and of the buildings which were on the western slopes of the Velia in the late Imperial era. As expected, on the site of the future Stazione Venezia the investigations of the First Phase showed a complex and uninterrupted stratigraphy starting from the Archaic and Republican ages (4th and 5th century BC) to now.
In the excavation in the centre of the square of Piazza Venezia, which reaches a depth of about 8 metres, the Via Flaminia was brought to light, flanked by a commercial and production area. It has only been possible to explore the deeper levels by means of coring, due to the rising groundwater, postponing the completion of the inspections which would lead to the Second Phase, i.e. the construction phase.
The excavations carried out in Piazza della Madonna di Loreto have revealed a monumental complex of major importance dating back to Hadrian’s era, consisting of three large rooms or classrooms (auditoria) where philosophical discussions and public readings of lectures took place. On this site the archaeological inspections of the First Phase ended with the request of the MibacT to enhance the monument, one of the largest archaeological discoveries in Rome in the last few decades, right in the area of the future Stazione Venezia.
Other important results have come from the investigations in the Via Cesare Battisti, where a luxurious domus with a peristyle with marble cladding and frescoes was found. For the design of the Stazione Torre Argentina two studies were carried out near the church of Sant’Andrea della Valle, where the monumental Porticus Boni Eventus and other structures relevant to the so-called Stagnum Agrippae were discovered.
The excavations in Piazza Sforza Cesarini for the Stazione Chiesa Nuova have revealed a complex sequence of construction phases: beneath the remains of a late ancient domus, the excavations brought to light a block of tufa datable between the end of the Republican era and the beginning of the Imperial era, and raised during Hadrian’s reign, belonging to a large artificial canal, the Euripus of Aggripa, identified under the Palazzo della Cancelleria.
Near the Tiber, at Piazza Pasquale Paoli, investigations were carried out for the Stazione San Pietro. The phases of the Roman era occupation are shown clearly here by imposing structures in irregularly built squared blocks of tufa along the banks of the river. Beyond the Tiber in the Prati-Delle Vittorie district, the considerable depth of the levels of archaeological sites has proved very useful for the knowledge of the ancient landscape. Coring has provided a complete reconstruction of the original morphology, the trend and distribution of ancient stratigraphy.
The final project was approved in 2009 and the Second Phase investigations began, within the context of the construction process. These investigations include specific core drilling in areas inside the perimeter of reinforced concrete. Once the area is safely secured, a complete archaeological excavation can be undertaken down to the sterile sediment. This phase is perhaps the most delicate because in many cases it involves working concurrently on different levels.
The First Functional Section, in which 29 sites were investigated (sections T7, T6A, T5 and T4), from the terminal at Pantano Borghese – where a neolithic settlement was discovered – to Stazione San Giovanni, has been completed. Current excavations are underway in the T3 section for Stazione Fori Imperiali and Stazione Amba Aradam.
In addition to archaeological discoveries, the preparatory coring and excavation investigations have allowed the reconstruction of the original morphology of a portion of land not yet changed by the intervention of Man. It is the area found outside the city walls between the Via Casilina Vecchia and Porta Metronia, along the T4 and T3 sections which were widely examined, up to the gardens of Via Sannio, next to Porta Asinaria and Piazzale Ipponio.
The enormous amount of data collected from these investigations have led to the progressive reconstruction of the geomorphological structure and the development of settlements from the pre-human age to the urbanization of the first few decades of the 20th century. The accumulated data have enabled a three-dimensional reconstruction showing the evolutionary phases of the landscape profoundly changed by the work of man and the control and management of the water resources of the land.
Before the transformation induced by human activity, the orography of the land between Via Labicana and Piazzale Metronio was characterized, in the eastern area, by a vast, high tufa plateau on which was built in a dominant and scenic position l’Anfiteatro Castrense,into which was carved a valley from Piazza Camerino to Via Monza. Between the plateau and the valley was a steep slope which at a height of about 20 metres began to slope more gently downwards. To the west of the Appia Nuova, on the opposite side of the valley, was another tufa plateau, one of the lowest areas corresponding to the current Piazzale Appia and Largo Brindisi where a vast reservoir was connected with the valley to the west of Porta Asinaria.
The appearance of the land, before the introduction of the artificial borders created by the building of the Aurelian walls in the third century AD was very complex with hills and valleys crossed by streams and courses of running water.
The settlement phases which occurred over the centuries in the belt outside the walls between San Giovanni and Porta Metronia are closely linked to the presence of the tributary water from the Tiber, called the “river” in the sixteenth century and named “Acqua Crabra” by Cicero, Frontinus and Procopius.
The large farm of the early Imperial age excavated in the Stazione San Giovanni was developed along the course of a ditch used for feeding complex irrigation systems and fed by a huge water reserve.
The barracks unearthed at a depth of 9 metres in the Stazione Amba Aradam, with their features of unity and extraordinary conservation, can be considered one of the most revealing archaeological discoveries of Rome in recent years. Dating back to the age of Emperor Hadrian, the barracks were abandoned, razed and partly buried during the construction of the Aurelian walls. On the sides of a long central corridor there are 39 rooms, 25 of which are square, a common feature in ancient Roman barracks.
The Amba Aradam complex is located on the slopes of the Celio, topographically characterized by the presence of other military buildings: the Castra Peregrina at the Santo Stefano Rotondo, the Statio V cohortis of the Vigili at the Santa Maria in Domnica, and the Castra Nova Equitum Singularium at San Giovanni in Laterano. Further down from the barracks the excavation of a domus is being completed.
Following this important discovery, and in order to safeguard the discoveries, the Superintendent of Archaeology of Rome, has redefined the architectural project to allow the relocation of antique structures inside the station and to put into context the findings by restoring the visual relationship with the Aurelian walls, and integrating this extraordinary discovery with the infrastructure.
The results of the excavations at the Stazione Fori Imperiali, carried out on several occasions and still underway, delineate with great precision the extension of the Velian Hill, destroyed in 1932, and the extent of the archaeological remains saved from demolition and preserved behind the Muro del Munoz and the Piazzale del Colosseo. These new acquisitions enrich the historical-topographical framework of this important sector of the central archaeological area, destroyed by the excavation work during the construction of the Via dell’Impero (now the Via dei Fori Imperiali) and the aboveground construction of the metropolitan line B.
The decision to place most of the station in the excavated part of the Velia greatly limits the interference with the archaeological stratigraphy in such a crucial area of ancient Rome.
The museum set-up already created in the Stazione San Giovanni, as a project for the ongoing in situ enhancement of the archaeological structure found at the Stazione Amba Aradam, confirms how the construction of large urban infrastructures such as Metro C represent an extraordinary opportunity for the enrichment of our historical-archaeological knowledge and the protection and care of new discoveries. The issue of the returning of archaeological resources to the public is of crucial importance for the correct construction of a work of such importance as that of the Metro C. The release of scientific data and the imparting to the citizens and station users of the discoveries made during the building of the Metro C constitute a fundamental step in the production process.