The Roman settlement of the is a modest Roman town situated between 1,000 and 1,150 meters in altitude, at the base of the Puy de Dôme and its sanctuary dedicated to Mercury. The settlement is located in the center of the territory of the Arverni city, in Aquitaine Gaul, about ten kilometers from its capital, Augustonemetum/Clermont-Ferrand.
The site of the col itself was occupied as early as the end of the protohistoric period, although the nature of this occupation remains unknown. The foundation of the secondary Roman settlement dates back to the first century AD. The settlement was structured by the between Lugdunum (Lyon) and Mediolanum Santonum (Saintes), covering between ten and fifteen hectares. It comprised four recognized sectors. The roadside station, situated at the col and close to the Agrippa road, represents the central nucleus of the settlement. While regulating the flow of travelers and pilgrims wishing to climb the Puy de Dôme to access the summit sanctuary of Mercury, its function probably was to provide lodging, food, and shops for travelers from all directions. The northern part of the site, which marks the point of departure for the ascent of the sacred mountain, features a cult area where a sanctuary once stood. This has been discerned through surveys and the ceramic study has confirmed its existence. In contrast, the funerary zone, situated in the southeast of the cult sector, encompasses one of the most substantial funeral pyres in Gaul, as revealed by archaeological excavation. The lower quarter, situated approximately 400 meters west of the col and adjacent to the Agrippa road, represents the final sector of the settlement. Its abandonment, which occurred after the mid-third century, remains a subject of historical inquiry.
Similar to the other territories of the Chaîne des Puys, the Col de Ceyssat has undergone significant reforestation efforts since the late 19th century. Despite the challenging terrain and limited accessibility, archaeological knowledge of the ancient settlement has primarily been shaped by systematic archaeological operations, surveys, and pedestrian prospections conducted under the guidance of from the University of Clermont-Ferrand. Additionally, some rescue archaeology surveys, associated with land development projects, have provided insights into the ancient town on an intermittent basis.
Contexts
Geographical context
The Col de Ceyssat is situated at the base of the southern slope of the Puy de Dôme, the highest peak in the Chaîne des Puys, which can be observed from a distance of at least several tens of kilometers. Peaking at 1,077 meters in altitude, the col was, until the 18th century, the primary communication route between the expansive Limagne plain to the east, the Dore mountains to the southwest, and the Combrailles to the northwest. The Col de Ceyssat itself corresponds to the tripoint between the communes of Ceyssat, Saint-Genès-Champanelle, and Orcines.
The settlement is situated at an altitude between 1,000 and 1,150 meters and is encircled by numerous volcanoes. To the north is the Puy Lacroix, formerly known as Puy. The southern flank of the Puy de Dôme which constitutes 40 to 50% of the volcano and is accessible via the Muleteers' Path. To the south is the , while to the southwest is the Puy Besace.
The climate is marked by some extreme weather conditions, including severe winters, violent storms during the summer months, and a high level of precipitation, in the form of rain and fog. The forest covering the col consists of spruces and beeches, planted between the late 19th and early 20th centuries as part of a large-scale reforestation program for the Chaîne des Puys. While this wooded relief occasionally presented challenges to research, it also served to protect the site by mitigating the erosion of the slopes, whose sediments have long covered the remains. This has allowed, for instance, the preservation of some walls at a height of more than a meter.
The geology of the Col de Ceyssat is defined by trachytic eruptive products from the Kilian explosion crater, which extend to the col. Human occupation during antiquity resulted in the construction of terraces that significantly altered the organization of the terrain until the site's abandonment and subsequent collapse.
Archaeological context
The archaeological site of the Col de Ceyssat is situated within the territory of the ancient Arverni city, which encompasses the entirety of the departments of Puy-de-Dôme and Cantal, the south and southeast of the department of Allier, and the northwest third of the department of Haute-Loire. The civitas Arvernorum is the successor state of the Gallic city of Arverni and was part of the province of Aquitaine. Its capital, Augustonemetum, was constructed at the end of the first century BC at the site of the future city of Clermont-Ferrand, situated approximately 10 kilometers east of the secondary settlement of the Col de Ceyssat.
Except for the Mercury temple located at the summit of the Puy de Dôme, the archaeological context of the settlement remains largely unstudied. However, several sites within a few kilometers of the settlement, in the communes of Ceyssat and Orcines, have been documented.
In the 1970s, the thermal section of a Roman villa was excavated approximately 4.5 kilometers west of the col itself (approximately 4 kilometers west of the lower quarter settlement). This site, known as "Prés Bonjean," is located in the commune of Ceyssat. Although the precise date of its occupation remains uncertain, it does not appear to extend beyond the end of the third century. In the commune of Orcines, to the east, at a place called La Baraque, approximately five kilometers from the col, the existence of another opulent rural residence, also interpreted as a villa, was revealed by the discovery of mosaic tesserae in the late nineteenth century. The final documented reference to a wealthy rural residence is located in the commune of Orcines, at a site known as Mazière/Mazeiras. A Gallic coin hoard was discovered in the mid-19th century, while significant Roman constructions were reported at the end of the same century, along with hypocaust tubules. Subsequent excavations were conducted in the 1980s, uncovering additional remains across an estimated 1-hectare area. While the authors of Carte archéologue du Puy-de-Dôme (Puy-de-Dôme Archaeological Map) interpret these findings as indicative of a villa, the excavator posits that they may represent a waystation situated before the ascent of the Puy de Dôme.
In the late 19th century, three inscriptions on domite were unearthed in the commune of Orcines, in a location designated as La Tourette. These inscriptions,All notices about the epigraphic inscriptions of the Arverni city, as published in 1996 (), are accessible in their entirety via the online database of the The notice number accompanying the pagination of each reference to is identical to the notice number available on the PETRAE website for each inscription. two of which are engraved on statues, constitute dedications to Mercury made by Vindonius SilvanusFirst inscription: Merc(urio) sacr(um) | Vindon(ius) | Siluanus (CIL XIII, 01518 archive): "Dedicated to Mercury, Vindonius Silvanus (offered this dedication)" (). Second inscription: [Mer]c(urio) sacr(um), Vind[on(ius)] Siluan[us] (CIL XIII, 01518 archive): "Dedicated to Mercury, Vindonius Silvanus (offered this statue)" (). Third inscription: Merc(urio) sạcr(um) | [Vi]ndọṇiu[s] | Silu[anus] ('CIL XIII, 01519 archive): "Dedicated to Mercury, Vindonius Silvanus (offered this statue)" (). and have been dated to the period between 151 and 180 by Bernard Rémy. Two additional, albeit more fragmentary,First inscription: MA (CIL XIII, 01520 archive (). Second inscription: ND (CIL XIII, 01520 archive (). inscriptions on domite were also documented later in the same century. Furthermore, another statue fragment and a trident, whose discovery was reported at La Baraque, are believed to originate from this site. The discovery of these three dedications led to the interpretation of the site as a small sanctuary of Mercury, situated close to the Roman road. Additionally, a milestone erected by Claudius was also unearthed in the surrounding area. However, despite extensive research conducted in 2019 at the same location, the precise location of the earlier discoveries could not be determined.
Historiography
Ancient discoveries
The earliest known reference to the discovery of human remains at the Col de Ceyssat can be traced back to the early nineteenth century. In his writings, Baron La Force mentions earlier excavations conducted by the architect Ledru, as well as his observations. The architectural terracotta, ceramics, and constructions are frequently reported throughout the same century, notably by Henri Lecoq, Jean-Baptiste Bouillet, and . The latter author dedicated a study to the Puy de Dôme in 1875, thereby enabling him to expand the inventory of discoveries made at the foot of the summit sanctuary.
Towards the end of the century, drew the attention of the Clermont-Ferrand Academy to the threats facing the archaeological remains. Following the destruction of a house by fire in 1886, two trenches, each measuring 20 × 2 meters, were opened up. Captain Noir de Chazournes, who had been tasked by General de Champvallier with surveying the site, observed "unequivocal traces of construction, but which, at first glance at least, do not reveal any significant monuments." The development of the col led to the discovery of additional artifacts, including architectural fragments and a stele unearthed during the excavation of foundations for a stable in the winter of 1886–1887. These items were subsequently transferred to the National Archaeology Museum.
Auguste Audollent, a professor of history at the University of Clermont, developed an interest in the summit of the Puy de Dôme when a funicular project was initiated and excavations were conducted at its summit under his direction and that of the architect . These excavations provided a valuable opportunity to gather information from workers and the local population, particularly regarding the discoveries made at the Col de Ceyssat. The construction of the new access road to the summit of the Puy de Dôme also resulted in the discovery of a statue in 1906. This was found at a depth of approximately 150 meters below the intersection of the new road with the path leading from Ceyssat to the summit of the Puy de Dôme. The fragment was identified as part of a landslide that had fallen from the embankment onto the snow of the trench.
The precise date of discovery is unknown for various finds that probably date to the late 19th or early 20th century. These include a bracelet donated by , a bronze statuette, a Hallstatt bracelet/leg ring, and common and sigillated ceramics.
The site was largely forgotten until the late 1950s and early 1960s when sporadic discoveries were made. However, the col is still referenced in publications on Roman roads.
The 1980s and 1990s were distinguished by a series of clandestine excavations.
Rediscovery of the site