During the period October 2022-February 2023, archaeological investigations will take place in order to excavate the two collapsed corridors (or ambulatories) on the southern front of the Colosseum. The area extends from the so-called Valadier buttress (fornix number LX) in the west to the so-called Stern buttress (fornix number XVIII) in the east, named after the two architects who, with a completely different theoretical approach, intervened during the 19th century to stop the collapse of the monument’s façade. The collapse of the two corridors occurred as a result of demolitions and natural causes (earthquakes) as early as the 6th to 7th century and continuously over the following centuries.
The south side of the Colosseum
THE EXCAVATION AREA
The area stretches about 200 linear metres. Once the framework of the pillars and vaults had been completely lost as a result of the collapses and demolitions, archaeological layers remain on the ground to be investigated in order to reach the level of the original travertine block pavement (partly visible to the east next to the monumental so-called Stern entrance) or the level of preparation of the paving itself.
WHAT WE WILL DO
First of all, we will proceed with the mechanical removal of the floor of sanpietrini (cobblestones) that covers the whole extension of the area: the aim of this first activity, preparatory to the archaeological excavation, is to remove the misperception of a pavement typical of an ‘external’ space (the sanpietrini) and, on the other hand, recover the perception and vision of an ‘internal’ space corresponding to the two collapsed ambulatories of the Colosseum.
The sanpietrini will be entirely recovered and reused for other activities in agreement with Roma Capitale. The archaeological excavation will thus provide a unique opportunity to investigate the construction site and the stratigraphy of the Colosseum, to reconstruct the history of the phases of use and reuse, and to give back to the monument and to the public its original imprint.
Over the last twenty years, this entire area has been the subject of excavations on single sectors (fornixes or galleries), also in collaboration with Roma Tre University, which has recently published a book presenting the results of the excavations and the finds (G. Facchin, R. Rea, R. Santangeli Valenzani, eds., Anfiteatro flavio. Trasformazioni e riusi, Electa 2018). These investigations are important because they have yielded fundamental information that has been widely taken into account for the success of the research.
Particular attention was paid to the sector of fornix V where the extrados of the vault of the so-called Passage of Commodus emerged, an underground corridor used by emperors to appear in the arena without being seen by the public.
The archaeological excavation will make use of small mechanical means for the modern levels and the topsoil, while it will be carried out manually and with a stratigraphic method in all the sectors that have never been thoroughly investigated.
THE RESTORATION AND THE NEW USE
Once the excavation has been completed and all its phases have been documented, a dimensioned survey will be carried out: this survey will be used for the design of the restoration of the space of the ambulatories recovered to the use and knowledge of the Colosseum.
The project, which will have to take into account the state of conservation of the surfaces that will have been exposed, the materials and the ancient levels of frequentation, will have to restore the perception of the original form of the Colosseum, with a design choice that will take into account the original travertine block paving, the levels of preparation and the infrastructures that will emerge.
In the next two years this large and demanding building site will therefore occupy the entire portion of the ‘Piazza’ that is currently not accessible to the public. The prospect is to open a new sector of the Colosseum to the public, extending the visitor routes, enhancing the cultural components and, above all, finally giving back to the monument its original geometry.
APPOINTMENTS WITH ARCHAEOLOGISTS: EXCAVATION AND COMMUNICATION
On Friday afternoons, an archaeologist will always be present to report on the progress of the excavations and explain the latest news from the investigations.
This page will also be continuously updated with further photos and videos.
DIG DIARY
6th October 2022: the footbridge that will allow the public to continue walking around the Colosseum without encountering interruptions has been completed. The footbridge skirts the excavation area and thus allows a privileged view of the ongoing activities. At the same time operations have begun to remove the sanpietrini platform located between fornices XVIII and XII, built in the early 2000s after the excavation that brought to light the original travertine pavement blocks of the first and second ambulatory of the Colosseum.
7th October 2022: the removal operations of the sanpietrini platform continue unabated, in order to bring back the travertine paving blocks already uncovered in previous years. The whole of next week ( 10th to 14th October) will be dedicated to these removals and to transporting the sanpietrini to the warehouses provided by the Municipality of Rome for their subsequent proper reuse.
10th October 2022: the sanpietrini removal operations have temporarily stopped: we are waiting to hear from the City of Rome regarding the storage location of the sanpietrini. In the meantime, we have wasted no time and have continued with the delimitation of the construction site area, by means of a “new jersey”-type fence and a barricade. The aim is to protect all passers-by but not to enclose all the operations within a fence.
11th October 2022: today we have completed the installation of the fence. In addition, we started to set up the new jersey with panels equipped with QR codes so that everyone can learn about our work. At the end of the day, the first loading for the first transport of sanpietrini to the depot provided by the municipality was completed.
12th October 2022: the removal of sand and sanpietrini can only take place between 7 and 9 a.m., when the Colosseum square is least crowded. The area freed from the sanpietrini has been cleaned and cleared of sand, leaving at least three concrete plinths reinforced with smooth rebar to emerge. We then started to re-excavate the sector between fornices XI and X: in the topsoil we found a coin of Victor Emmanuel III. The layer however – as mentioned – is entirely reworked.
13th October 2022: rainy day. A transport of sanpietrini was carried to the depot of the Municipality of Rome. Arrangements have been made with Acea for the management of the public lighting sub-services that are emerging from the first layers of soil fill. Finally, we took advantage of the historical research needed to contextualise in time and function the concrete plinths found. We found detailed documentation attesting to a massive consolidation and safety intervention of the east front of the Colosseum in the late 1970s, carried out – among other things – with an emergency bracing placed on temporary blocks of reinforced concrete connected with temporary bolts to the ancient structures after interposing sheets of plastic insulating material (more information can be found in the document that can be downloaded here).
14th October 2022: Today, the transport of the sanpietrini towards the municipal depot continued, and the removal of the earth fill that in 2018 had sealed the end of Roma Tre University excavation in front of fornices X and XI began. We found the protective fabric and at the same time highlighted the traces of the public lighting sub-services. We knew that we would intercept this network, and as early as Monday 17th October the Acea team will be on site to support us in moving it.
17th October 2022: excavation of the backfill levels continued in the areas already investigated in previous years, together with the removal of the cobblestones covering the entire extent of the site. In the late morning, Acea and Areti operators carried out an inspection to ascertain the extent and positioning of the lighting cables, planning to move them quickly to allow the investigation to continue safely.
18th-19th-20th-21st October 2022: the investigations proceeded, still remaining on the modern fill levels and on the sanpietrini platform. However, the Roma Tre excavation sample in front of the XI fornix was partially reopened, thus bringing to light part of the preparation of the original travertine blocks.
24th-25th October 2022: during these two days, worksite activities are suspended to allow for the setting up of ‘The Cry for Peace’ ceremony in the presence of Pope Francis.
26th-28th October 2022: the excavation of the previously investigated areas with disposal of the backfill continues. The foundation of the Colosseum has thus been brought back to light with the traces of the travertine blocks of the original pavement, already investigated by Roma Tre in 2017-2018.
31st October, 2nd November 2022: the gradual removal of the sanpietrini in the sector between the fornices XVIII and XII continues. In the meantime, the sector between fornices IV, V, VI has begun to be cleared. The area had already been extensively altered in the past – between the 1990s and the year 2000 – when it became necessary to cover the Passage of Commodus, in order to restore the ancient layout and safeguard part of the stuccoes that still exist. At least two shafts emerged from the excavation, which do not seem to correspond to the windows present in the underground passage.
2nd-4th November: the excavation continues by clearing fornices IV, V, VI of the backfill soil, and the modern extrados of the vault of the Passage of Commodus is revealed. This was carried out in the 1990s when, in order to cope with the microclimate problem, the Passage of Commodus was entirely excavated and at the same time received extensive restoration and waterproofing work on the entire extrados of the vault. The pictures show the current arrangement, after the excavation of these days.
7th-9th November 2022: after exposing the vault of the Passage of Commodus, the excavation continued inside fornix VI in the portion close to the plinth where an earlier excavation, dating back to the 1990s, documented in the archive files, was intercepted. As can be seen from the survey that can be downloaded here, the excavation intercepted the preparation of the travertine floor blocks that we now find under a geotextile sheet.
14th November 2022: due to adverse weather conditions, the research was temporarily suspended.
15th November 2022: today we braved the weather as the archaeological excavation is finally reaching the levels in place and the first interesting data is already beginning to emerge. Inside the fornix VI we have found a collapse level (pertaining to the vault of one of the two lost corridors/ambulacra) that insists on the spoliation levels of the travertine pavement blocks (the imprints of which are clearly recognisable near the plinth). These very first pieces of information, correlated with what was found in the excavation of the fornices XI and X preliminarily provide some indications on the actions that took place over time, in particular on the removal of the travertines – presumably dating back to the early Middle Ages (11th-12th centuries) – and on the definitive collapse of what remained of the vaults (from the 14th-15th centuries onwards).
16th-18th November 2022: unusually rainy days forced the suspension of the excavation. In order to be able to proceed with the research, however, the intervention of Acea operators has now become unavoidable. Along the entire edge of the excavation on the side of the Colosseum’s arches run the cables carrying the monument’s artistic lighting. Acea’s intervention foresees the interruption of power to allow safe archaeological research and the temporary relocation of the power cables outside the site area. In order to be able to proceed in this direction, for the next ten days at least, the Colosseum will be deprived of artistic evening lighting.
21st November 2022: Acea secured the site area to allow excavation of the levels where the lighting cables are located. The removal of the soil filling inside the fornix IV continues, and the removal of the cobblestones on the side between fornices LXXVI and LXII has begun.
22nd November 2022: heavy rain prevented work from being carried out today.
23rd-24th-25th November 2022: the entire excavation area up to the visitors’ exit has been cleared of sanpietrini. The excavation can finally get to the heart of the stratigraphic investigations in the wedges of the fornices that have never been investigated in depth, particularly those between fornices IX and VI. From Wednesday 30th November it is our intention to increase the teams working to unite the excavation fronts, both those already investigated by Roma Tre University and those that have never been excavated.
28th-30th November 2022: these are very busy days, with large movements of sanpietrini and topsoil being removed to completely clear the archways within which the vault of the Passage of Commodus and the drainage pipes built for water disposal are located. Disused cast-iron pipes also emerged and will be disposed of. On the sector between the exit of the Colosseum and the entrance under the Valadier buttress, the excavators have almost completed the removal of all the sanpietrini and – as expected – the travertine blocks of the original paving are emerging. The month of December will be entirely dedicated to the stratigraphic excavation of the fornices I-II and VI-X. We hope to find still little known fragments of the Colosseum’s history.
1st December 2022: we did a bit of archive research, to get a good understanding of how the modern portion of the vault of the Passage of Commodus was built, how the windows were arranged, and to see if the archive photos can tell us the function of the pipes and drains, ancient and modern. Here is an interesting gallery of images in which we have juxtaposed the archive photo with the current situation.
2nd December 2022: We have completed all the removal of the sanpietrini on the so-called Valadier sector, i.e. between the public exit and the entrance. Here the ancient travertine pavement surfaces under a few centimetres of topsoil, which we are removing with mechanical means, working very carefully. In the topsoil we find pottery from the 6th century AD to the present day (!) including plates and cutlery!
5th December 2022: stratigraphic excavation work has finally begun in the area of fornices II and III near the public exit. There is no shortage of (bitter) surprises: we intercepted a clean cut in the late antique layers made in modern times for the laying of a reinforced concrete pipe. In the filling we also found a glass bottle, which you recognise in the photo, very similar to those used in pharmacies in the early 20th century to contain cough syrup (or so it seems to us). Over the next few days we will try to figure out where it goes. The only positive note is that this cut has allowed us to expose the entire section and reach the height of the original travertine paving blocks.
7th December 2022: In the so-called Valadier sector, the removal of the earthworks is proceeding apace, uncovering the cement preparation of the travertine pavement blocks. We have decided to leave a 5 cm layer of soil to protect the surface, which we will remove by hand when we have uncovered everything. In the so-called Stern sector, we have removed the pipe and are investigating further.
12th-16th December 2022: it was a week of rain that prevented continuous work. In the so-called Valadier sector, the excavators were able to continue with the removal of the earthworks, also clarifying the limit of the metro B construction site and to a large extent also justifying the presence of very heterogeneous material.
In the so-called Stern sector, on the other hand, and in the vicinity of fornices II and I (where excavations will be concentrated in the coming days), the beaten layer cut by the concrete pipe trench was cleared and an evident dark-coloured layer emerged, also rich in charcoal, where travertine blocks in place aligned with the pillars of the preserved façade.
19th-22nd December: in the Valadier sector, mechanical excavation of the backfill levels continued at a fast pace. In addition to the Acea cables and a deep hole for the laying of conduits, a number of “arrangements” of more compact soil begin to emerge, even in contact with the blocks of the original travertine pavement. We have noticed that these ‘arrangements’ are located in correspondence with the fornices without stairs and therefore at an alternating pattern (one on and one off). By the end of the year (30th December), when the mechanical excavation is scheduled to be completed, we will be able to understand whether this pattern is maintained up to fornix LXXVI (public exit) and what its function is.
27th-30th December: the last week of the year brought interesting news. On the so-called Valadier sector, the removal of the basements up to 5 cm was completed, revealing both the cement preparation and some blocks of the original flooring that were saved from spoliation. This sector retains some “structural evidence” that will be better investigated in the coming weeks when we will start cleaning the entire front with a stratigraphic approach.
In the so-called Stern sector between fornices II and IV, the archaeological excavation at the moment seems to confirm the stratigraphic sequence with levels from the Renaissance and late medieval age (from the 16th century onwards) containing residues from the Roman age still linked to the building’s use as a place of entertainment, as revealed by the pottery, glazed tiles (for which we would like to thank Dr. Marco Ricci) and coins (for which we would like to thank Dr. Fabio Scatolini). In fact, it is well known that this area was subjected to removal in the late medieval age and even to excavation (carried out from the end of the 18th century and then during the 19th century during the great 19th-century restoration works), which are now the reason for numerous gaps in the archaeological documentation in the period between the 5th century (when the building for entertainment began to be dismantled) up to the 13th century.
3rd-5th January 2023: In the first days of the year we focused our attention on the so-called Valadier sector, where we exposed almost the entire cement bedding of the paving blocks, which we can now read perfectly in all their impressive 80-90 cm thickness. We also focused on cleaning near wedge 68 the association of the travertine block with what we had called “evidence” / “arrangement” of a structural character and which we understood better. This structure had also been seen by the Roma Tre team inside wedge X (without understanding it) and it is therefore important to have now clarified what it looks like: it appears to be a concrete conglomerate structure characterised by a very tenacious purple mortar, which rests on the block of travertine that has been suitably excavated and shaped to facilitate the association. We can only give a physical relationship by saying that this structure is posterior to the travertine block but it is too early to attribute its function and chronology. In any case, over the next few days we will continue with the cleaning of the walls and levels with collapses found on them in order to understand their connections.
The entire area will now be surveyed by the topographer, who will also focus on the so-called Stern sector to document the layers before proceeding with the archaeological excavation.
9th-13th January 2023: This week we defined some very important aspects, for the knowledge and strategy of the excavation. The most important and most delicate thing for the management of the monument was the consignment to the company of the SOUTH fornix, i.e. the exit for the public: in order to be able to investigate this area as well, we moved the exit to the next fornix. We hope not to cause too much inconvenience and we trust in the cooperation of all our visitors. Then we expanded the sector of fornix 74 into the so-called Valadier sector, reaching also in this area, which has been disrupted by modern backfills, the top of the cement foundation and the impost of a radial gutter notched by a cast-iron pipe, which was removed to the extent possible.
So-called Valadier sector. Radial gutter partly disrupted by the laying of a cast-iron pipe
Another in-depth investigation we carried out this week concerned the so-called structures or elevations, spared in correspondence of fornices 62, 64, 66 and 68: we tried to ask ourselves the meaning of these “structures” that are placed in correspondence of wedges either completely free up to the crown of the podium or interrupted by stairs facing the second order. For a better understanding of these arrangements we are verifying the paths of circulation and fruition of the Colosseum, in ancient but especially in post-antique times. Perhaps it is not by chance that two blocks of the original travertine pavement have been preserved at wedges 62 and 68, which you can also see in the plan below: is it possible that they are property boundaries? We shall see.
In the so-called Stern sector, on the other hand, excavation of the late mediaeval frequentation levels continues in fornices 1 and 2. Layers rich in ceramic material and in situ collapses begin to appear.
16th-20th January 2023: a very rainy week with very erratic site progress. However, we opened the new excavation site, at the public exit, after the previous week’s handover.
23rd-25th January 2023: the excavation was finally uninterrupted for at least three days. The ACEA Areti operators moved the underground utilities, allowing the workers and archaeologists to proceed safely under the pipelines. From an archaeological point of view, the levels of frequentation in correspondence with the SOUTH fornices, 1 and 2 (towards the Stern buttress) are well defined, with shafts of ceramic material still dating back to the late Middle Ages, and sectors with an abundant presence of marble and travertine, suggesting that these are accumulations of material from the spoliation inside the monument.
30th January – 4th February 2023: this week we focused our attention on two different fronts. We began a systematic investigation of the ‘elevations’ found in the Valadier sector, in order to better understand their limits in relation to the preparation of the travertine blocks of the original pavement. In some places, the elevations rest on a plane of pressed travertine flakes that extends even above the preparation of the blocks themselves.
In the Stern sector, meanwhile, the excavation continues exposing levels of frequentation and accumulations of material with steep south-southeast gradients.
This week we also focused on the V fornix where the vault of the passage of Commodus is located, because we will have to study an ad hoc roofing and waterproofing project. Thanks to our colleague Daniele Nepi, we obtained some suggestive images between the hypogeum passage and the extrados, also verifying the orientation of the vents towards the south-east.
9th-14th February 2023: in these days the excavation is proceeding at a rapid pace in the SOUTH fornices, 1-3 of the so-called Stern sector, and the archaeological data provide important information regarding the post-ancient phases of the Colosseum. In particular, it is evident how the single wedges/fornices show very different situations and modalities of frequentation: for example in the SOUTH fornix (the one corresponding to the exit of the public to be clear) we are investigating patches of surface arrangement with a well-structured ballast that would seem to be functional for the passage from the outside to the inside. On the other hand, in the adjoining fornices, stratigraphies between the 9th and 12th centuries AD emerge (on the basis of the ceramic materials found) characterised by brown sediments, also rich in charcoal, belonging to activities that were not necessarily carried out in situ and that were therefore removed or moved (perhaps even from the interior?) during the extensive phase of the spoliation of the travertine pavement blocks that can be dated to the 12th-13th centuries. On these levels one also finds collapses (or rubble) pertaining to the levels of the second order, which contain, among other things, numerous remnants of opus spicatum bricks pertaining to the pavements of the same second order. In general, we find ourselves – as they say in the jargon – on the “head” of levels that are not yet completely in their primary position, but which we will progressively better understand and analyse as the excavation proceeds to fully expose these levels.
15th-22nd February 2023: the most important results of this week concern first of all the definition of the chronological horizons of the strata we are excavating in the South and 1st arches analysed by Dr Marco Ricci (whom we thank). The ceramic materials mainly date back to the first half of the 13th century, providing indications of the spoliation of the travertine blocks, which occurred in an earlier period (as we continue, we will be narrowing the chronological range further). These days we have also updated the documentation, especially with regard to absolute quotas.
23rd February-3rd March 2023: the excavation focused on the SOUTH fornix in order to be able to provide for the reopening of the public exit as soon as possible. There were many surprises. In particular, we exposed the cement foundation of the Colosseum “apparently” excavated on a tenacious silt-sandy layer. In order to better understand this sequence, which sheds light – if possible – on the project of the Colosseum’s implantation on this front of the valley affected by the passage of the Labican ditch, we asked the advice of Dr Carlo Rosa, geologist. The “sands” seem to be positioned close to the foundation (which cuts them?) both eastwards and westwards, leaving free the intermediate space occupied by the extrados of the south tunnel.
6th-10th March 2023: the answer to the question of the presence of this consistent level of sand has not yet been addressed, but we are aiming to better understand the issue by observing the behaviour of the cement foundation in fornix 1 and fornix 76. In the meantime, we are in the process of backfilling the SUD fornix to reopen it to the public and excavating the substantial collapse of fornix 1: and here came a beautiful discovery that will be the bearer of very important data. We have found the almost intact skeleton of an equid (we thank Prof. Claudia Minniti) crushed by a collapse. Now the archaeological excavation will have to proceed by levels, and as soon as possible we will be able to sample the animal’s bones, in order to identify its dating using the C14: we hope it will confirm the famous earthquake of 1349 also cited by Petrarch in the Epistles to the Familiares: ‘tam graviter ut ab eadem urbe condita supra duo annorum milia tale nihil acciderit’, ‘nothing so violent in the last two thousand years had ever managed to devastate the city’ (Petrarch, Fam., 10, 2).
13th-17th March 2023: during these days we focused on the equid thanks to the invaluable support of Prof. Claudia Minniti of the University of Salento. With her expertise, we waited for the best moment to free the skeleton from the collapse it was in. We will now carry out C14 analyses to be able to date the period of death and also give our stratigraphic sequence absolute chronologies.
In the meantime, we have also begun backfilling the SOUTH fornix to restore the public exit from the Colosseum, which will be operational again from the week of the 27th of March.
27th-31st March 2023: in this week the activities were concentrated on the backfilling of the SOUTH fornix to restore the public exit. At the same time, investigations continued in fornix 1 where levels of attendance and levels of spoliation continue to emerge. In April we expect to verify this situation more thoroughly.
3rd-21st April 2023: during these weeks, which were interrupted by the Stations of the Cross celebrations and the Easter holidays, the excavation of fornix 1 was completed up to the foundation slab. As we had expected, on the basis of what had been found in fornices 60-70 regarding the presence of the so-called “rises” in correspondence with the free fornices, a “rise” was also found in fornix 1, very well preserved in its mighty pozzolana and tuff formwork structure, approximately 42/45 cm high. The traces of the joints of the travertine pavement blocks – completely stripped – left on the preparation mortar run flush with the ‘raised’ and, following an intentional fretting, do not appear to continue. If these readings were to be confirmed in the following, we could at this point advance the hypothesis – contrary to that advanced in recent months (see January’s diary) – that these “rises” are in phase with the design and related installation of the pavement and functional to create the base for travertine blocks no longer about 90 cm thick/height, but about half that.
At the beginning of May, fornices 1-3 were backfilled. This is the plan at the end of the excavation.
2nd-22nd May 2023: Despite the many days of rain, excavation was resumed in the so-called Valadier sector in fornices 68-74, which are characterised by the presence of underground utilities and backfill levels.