The Grotta dei Santi opens in cavernous limestone on the south-eastern side of the Argentario promontory. The cavity is formed by one vast chamber, 45 m long and 40 m wide (maximum). It is known that research took place in the cavern in 1869, but it was Aldo Segre who provided a precise stratigraphic description in 1959. From 2008 onwards, the SBA of Tuscany and the University of Siena, in collaboration with the University of Pisa have renewed work on the site. The main aim of the new exploration was to assess the thickness of the deposit described by Segre. Overall, the present situation generally corresponds with the lithological units he identified. In 2013, it was decided to proceed with a systematic investigation, given the cavern’s scientific importance and the fact that the prehistoric deposit appears to be eroded by the sea during heavy storms. This erosion risks further damage to the Musterian levels already removed from the part of the cavern closest to the entrance from the ingression of the Holocene sea. The campaign produced the following results: 1. planning of the cavern; 2. layout of the grid and level 0; 3. new work on the exposed stratigraphy; 4. _sondages_ in the Musterian deposit. As regards point 3, all of the disturbed soil was removed revealing the _in situ_ stratigraphy. This led to the identification of a series of Musterian horizons with hearths (denominated 110, 111, 1004). Horizon1004 was was quite thick and extended horizontally for at least 12 m2. It was sealed by a clay sediment, and formed by at least three episodes of Neanderthal occupation. The excavation of _sondages_ in the Musterian deposit was limited to: - the opening of just under one m2 (quadrant H2) in horizon 1004; - the excavation of level 111 in quadrant G5; - the excavation of a _sondage_ (1 x 1 m) below the thick base stalagmite. The 2013 campaign marked a decisive step in the evaluation of the Grotta dei Santi. In fact, if its importance in the Tuscan prehistoric panorama and more widely that of central Italy) was initially recognised, today it can be said that the Grotta dei Santi is one of the most significant Neanderthal deposits in Europe.

This season, the main objective was to begin excavation of the _in situ_ Mousterian levels (the deposits covering them were removed last year), and the collection of sediment samples and samples from several hearths for various types of radiometric dating and micro-morphological analyses. The excavations investigated all of the occupation layers to varying degrees. The upper horizons (levels 110 and 111) were investigated in quadrants G7, H6, I5, I6, and L5. A surface characterised by the presence of two hearths and a scatter of numerous artefacts, faunal and malacofaunal remains was exposed in tg.2 of level 111. One of the hearths (H6 111 tg 2) had been badly damaged by a large burrow. However, it was possible to calculate an approximate diameter of 60 cm and maximum thickness of 5-7 cm from the surviving part. The second hearth (I5 111 tg 2) was intact, at least in the part excavated to date. As regards the intermediate horizon, represented by level 150, the relative paleo-surface was exposed in quadrants F6, F7, H5, G5, G6, and I4. Another hearth was present in this occupation level and the surface was also rich in faunal and malacofaunal remains. The hearth remains to be excavated but was seen to have been partially eroded by the Holocene sea. The thick layer of sterile clay (900) sealing horizon 1004 was excavated in quadrants F3, F4, G3, G4, H2, H3, H4. The 2013 campaign had definitively revealed the great potential and exceptionality of the archaeological record preserved in the Grotta dei Santi that makes it one of the most important European sites for the middle Paleolithic period. The 2014 excavations consolidated a series of national and international collaborations that confirm the consideration afforded the site by the international scientific community. In addition to the consolidated collaboration with Sao Paolo University, Brazil, an official partnership has been set up with the Max Plank Institute for Evolutionary Anthropology in Lipsia. Collaboration continues with Pisa University (with the participation of Florence University) for the dating of the speleothems and geo-radar investigation of the deposit.

The 2015 campaign continued the investigation of the Mousterian levels. Quadrants M4, M5, M6 and M7 (quadrants II-III) and L6, L7, I7, H7, F8, E8, D8, D9, C8, C9 where excavation was limited to layers 105, 107 and 110, in order to extend the available surface prior to continuing the excavation of the occupation surface present in layer 111. In addition, charcoal samples were taken for radiocarbon dating from the hearth in layer 1004A. In order to expose layer 110 (lying immediately below layer107- hyena burrow), layers 105 and 107 (non-anthropic layers with traces left by hyenas) were excavated in quadrants M4, M5, M6 and M7 (quadrants II-III), L6, L7 and to a limited extent 107, also in I7. Layer 110 was then excavated (occupation evidence alternating with evidence of the presence of hyenas) in quadrants M4, M5, M6 and M7 (quadrants II-III) and L6, L7, I7, H7, F8, E8, D8, D9, C8, C9. In quadrants C8 and C10, at the base of layer 110, a flint knapping area was identified next to a large fallen boulder, which probably functioned as a seat. In quadrants D8, D9, and C9, adjacent to the flint knapping area, also at the base of layer 110, a surface was identified. Of limited extent, it was formed by cobbles and stalagmite fragments and probably man-made. Once the excavation of layer 110 was completed, the large burrow (badger or porcupine?) in quadrant L6, known from previous campaigns, was cleaned out. During the 2015 season, collaboration continued with both national (Pisa and Florence universities, and the Institute of Human Paleontology – IsiPU) and international (San Paolo University and the Max Planck Institute for Evolutionary Anthropology, Leipzig) institutions. Work continued on a series of studies whose main aim is to clarify the site’s chronology. Radiocarbon dating is being carried out on vegetal charcoal samples, OSL on sediment samples, dating of the stalagmites and georadar survey. During the year, study continued on the technology and function study of the lithic industry as well as the taxonomy and taphonomy of the faunal remains from the occupation level in layer 150. This data was subjected to integrated analyses within a GIS platform. Research is also ongoing with regard to the palaeographic, palaeo-climatic, and palaeo-environmental picture, in particular the ancient sea level and therefore the distance from the cavern to the coast.

The aim of this campaign was to continue the investigation of the Mousterian evidence in levels 110 and 111. Two separate areas were excavated, comprising respectively quadrants M4, M5, M6, M7 (quadrants II-III), L5, L6, L7, I6, I7, H6, H7 (Area A) and F8, F9, E8, E9, D8, D9, C8, C9 (Area B). During the previous season, the roof of level 111 had been uncovered in Area A, and in part of Area B, a horizon denominated “cobblestone surface”, belonging to level 110. In Area A cuts 1 and 2 were made in level 111. In level 111/1, a series of sub levels were identified: 111/1b, 111/0, 111/1c, 111/1. Sub-level 111/1b, devoid of anthropological evidence, contained abundant coprolites; some still structured, but mainly crushed and fragmented. The level deepened with a series of sub-circular and oval depressions probably caused by the activity of hyenas (burrows). Therefore, cut 1b represents a phase during which man abandoned the cave and hyenas took up residence, their presence attested until the base of level 110. The base of a hearth was found in cut 111/1c, partially resting on the roof of the underlying clay (111/1a). At the roof of 111/2 there was a well-preserved palaeo-surface. Within this level (often in contact with the roof of underlying 111/3), several hearths were identified, which were in varying states of preservation. Indeed, all that remained of some of the unstructured hearths was the reddening at the base, while the ash was well-preserved in others. The accumulation of lithic raw materials in Area B was completely exposed and dismantled. This had been defined as a cobblestone surface due to the presence of small rounded limestone blocks. What emerged below it was a work area where the extraction of bone marrow took place, characterised by numerous fragmented bones of large ungulates and the presence of large hammer stones. This season, collaboration continued with Pisa University, the Institute of Human Paleontology-ISiPU, and the Max Planck Institute for Evolutionary Anthropology-Leipzig, continuing work on a series of studies whose main aim is to gain a better picture of the site’s chronology. Radiometric dating on charcoal samples, OSL on sediment samples, and the dating of stalagmites are currently being carried out. During 2015-2016, studies continued on the technology and function of the lithic industry as did the taxonomic and taphonomic studies of the faunal remains from levels 150 and 110. This data is then integrated into a GIS platform. Research is also being undertaken on the palaeo-geographical, climatic, and environmental profiles, in particular regarding the ancient sea level and therefore its distance from the coast. As in previous years, indispensible logistical support was provided by Grosseto fire brigade, the Porto Ercole District Maritime Office, Monte Argentario town council, the Accademia Mare Ambiente of Porto Santo Stefano, Porto Ercole Red Cross and the Monte Argentario Divers. Students from Siena and Ferrara Universities, together with academic staff and researchers from Siena and Pisa Universities took part in the excavations.

This season’s campaign aimed to continue the investigation of the Mousterian remains in layers 111 and 1004, therefore the removal of the sterile layers between layers 111 and 150, in order to extend the excavation area of the latter. Three distinct sectors were investigated: “Area A” (H6, H7, I5, I6, I7, L4/I-II, L5, L6, L7, M4/II-III, M5/II-III, M6/II-III, M7/II-III),“Area B” (D8, D9, E8, E9, F8, F9, G8) and “Area C” (D5, E4, E5, F3, F4, F5, G2, G3, G4, H2, H3, H4). In Area A, the excavation of layer 111 (removing 111/2 and 111/3) was completed. These spits contained evidence of various combustion structures, some very well-preserved, that were individually recorded and, where possible, sampled for micro-stratigraphic studies. In this same sector, the sterile layers 120 (clay) and 121 (fine grained sand) were also excavated, reaching the top of 125 (medium grained sand with anthropological evidence and coprolites). In the adjacent Area B, it was possible to link the layers of ‘cobbled surfaces’ and the ‘area for marrow extraction’, respectively, with the base of layer 110 and layer 111/0, identified during the previous campaign, in Area A. The excavations continued and identified the first anthropic surface in layer 111 in the quadrants towards the rear of the cave, while in the rest of the area (quadrants towards the cave entrance) layer 110 was seen to rest directly on 1004. Indeed, in this sector the entire sequence becomes flattened, resting on large collapsed blocks that rise towards the right side of the cave. Lastly, in Area C _sondages_ were opened in the first anthropic levels in layer 1004. Once the first thin sterile layer was removed, the first surface was exposed (1004A) containing a large amount of anthropic materials, which covered a complex sequence of levels connected by lateral contacts, probably relating to a large palimpsest of hearths. This season, the established national and international collaborations continued (University of Pisa, Institute of Human Palaeontology – IsiPU and Max Planck Institute for Evolutionary Anthropology Leipzig). This involves a series of studies mainly aimed at further defining the site’s chronology (radiometric dating on vegetal carbon, OSL on sediment samples), identifying possible ancient DNA residue (possibly Neanderthal) conserved in the sediments and the study of the micro-morphology of the hearths through thin-sectioning. During the 2016-2017 campaigns, the technological and functional study of the lithic industry continued together with the tassonomic and taphanomic study of the faunal remains from levels 150 and 110. The resulting data has been analysed using a specifically designed GIS platform. More generally, the palaeo-geographic, palaeo-climatic, and palaeo-environmental profiles are also the subject of research, in particular the ancient sea level and therefore the cave’s distance from the coast.