Hazel Blair explores ancient Celtic roots beneath early Christian Geneva.

The deceptive neo-Classical façade and entrance to St Pierre Cathedral (Photo: H Blair).

In the 21st century, Geneva is a lively hub of international politics and underground quantum research, but archaeologists should not feel out of place in this lakeside cosmopolis: if your passion for stratigraphy trumps your interest in the Higgs boson, Geneva has another secret subterranean complex well-worth exploring, hidden in plain sight beneath the city’s cathedral.

Located at the top of a steep hill in the centre of Geneva’s Old Town, the Cathedral of St Pierre is reached via a handful of charming cobbled streets, leading up the ancient mound from the modern city below. I walked up Rue Jean-Calvin, named after the Protestant theologian who used St Pierre as a base to preach his own personal brand of Reformed theology in the middle of the 16th century. The cathedral has remained Calvinist to this day, but do not be fooled by its stark interior and neo-Classical façade: this Romano-Gothic church has deep roots stretching back to Celtic Gaul.

The region around Lake Geneva has been settled for millennia, but the city itself first entered the historical record in the opening chapters of Caesar’s De Bello Gallico, where it was described as a frontier town occupied by the Allobroges, a Gallic tribe Caesar labelled ‘recently subdued’. The Allobroges occupied Geneva in the 2nd century BC, until the town fell to the Romans c.120 BC.

Geneva then became part of Roman Transalpine Gaul, graduating to city status sometime in the 3rd century AD. The city underwent Christianisation, and was designated an important episcopal seat by the 4th century AD. So, though Geneva is generally remembered as a hotbed of Reformed thinking, the history of this early Christian centre is just as Celtic, and just as Catholic, as it is Calvinist.

Model showing the layout of the three early cathedrals (Photo: Alain Germond).

A sacred underworld

Archaeologists first explored the area beneath the cathedral in 1976, under the directorship of cantonal archaeologist Charles Bonnet. Now 30 years of research has culminated in the creation of a modern, well-interpreted, and accessible archaeological site that explores the wonderfully complex nature of the cathedral’s history.

A model at the entrance to the archaeological site reveals that, during the early Christian period, three separate cathedrals were built on the area now occupied by St Pierre. Each initially served a distinct function, and all were subsumed into a single cathedral in the late 11th or early 12th century. Armed with my audio guide, I set off to find out more about this so-called ‘episcopal group’ of the 4th to 11th centuries.

My journey into St Pierre’s sacred underworld took me first to the main entrance of the earliest and northernmost ancestor of the present-day cathedral. Dating from late antiquity, this first Christian complex was completed c.AD 380. It included a cathedral, a baptistery, and a church that may have been dedicated to the cult of relics.

The north cathedral was around 32m long by 15m wide, and primarily designed to serve the Christian public. One can still make out its main doorway in the middle of the cathedral’s southern wall, and here the threshold is in an excellent state of preservation, though visibly worn – presumably eroded by the pious feet of lay Christians eager to congregate in the nave.

But this early building also included private spaces. Walking along an elevated metal walkway that weaves in and out of the cathedral’s earliest recesses, I soon passed the early medieval monks’ cells that backed on to the exterior of the first cathedral’s northern wall. These were once occupied by Christian recluses who, imitating the Desert Fathers, shut themselves away from the world to focus their love of God through prayer, contemplation, and ascetic practice. Excavation revealed a network of water pipes that delivered heat to the small chambers, making life in these cells more comfortable than one might initially have imagined.

Given the organic development of the entire cathedral complex, one of the greatest challenges for visitors exploring underground St Pierre is unpicking the tangle of visible stone and assigning its constituent parts to the correct historical eras. In this 3,300m² excavation, one frequently stumbles across areas where the boundaries of Roman, early medieval, and Romanesque structures unapologetically intersect. Not every inch of stone can be labelled, but a helpful colour-coding system is employed throughout the manifold remains, helping visitors keep track of their whereabouts in relation to the different strands of time represented in the rubble.

Making my way east, I left the north cathedral and headed towards the baptistery, housed in its own building. Closely linked with Christianisation, early baptism was a hugely important cleansing process, being the ritual through which converts were officially welcomed into the salvific arms of Christianity.

The development of St Pierre’s successive baptisteries in this section of the site between the 4th and 8th centuries AD underscores Geneva’s importance as an early centre of Christianity. Particularly eye-catching was a large and remarkably preserved early baptismal font, dating from a time when the process of baptism typically involved full immersion.

The decorated stucco choir screen of the eastern cathedral (Photo: H Blair).

Bones and relics

Advancing further eastward, I came to the square-shaped ‘east cathedral’, built between the 7th and 8th centuries AD (the latest of the three cathedrals). This cathedral was closely linked with funerary worship, and was built over the remains of a 4th-century church dedicated to relics. Its centrepiece was a mighty sarcophagus that rested on the choir, where the faithful were drawn to pray.

The 1st-century BC cult burial of an Allobrogian warrior chief, whose skull has been ritually exhumed via the hole above his head (Photo: H Blair).

Although the eastern cathedral later became the episcopal complex’s main cathedral, there was less physical ground to cover here than in the north cathedral and baptistery. This might be explained by the fact that the eastern cathedral has been continuously transformed and extended over the centuries, so much so that, in effect, much of it is still in use today. Nevertheless, I was intrigued by what was visible of this early monument, especially its impressively decorated stucco choir screen, the base of which is surprisingly well preserved and clearly visible thanks to its striking Greek-inspired pattern.

Exquisite finds, models, interpretation boards, and audio-visual presentations are sprinkled throughout the archaeological trail, enabling experts and novices to enjoy this intricate site together. I was pleased to hear the audio-guide point out the error in the 1992 scale-model depicting early medieval Geneva. The model presents a dated reconstruction of the city’s waterfront, giving the impression that there were few buildings there in the 6th century. In fact, recent excavation revealed the opposite to be true, but the mistake is really quite poetic: just as this Christian complex was continuously shifting in space and time, so too is the practice of archaeology ever in development.

After watching an informative film about the development of the excavations, I made my way through a labyrinth of muddy walls – a fascinating warren of cross-sections – towards what, for me, was the star attraction: the 1st-century BC tomb of an ancient Allobrogian chieftain buried below the modern cathedral’s antechoir.

The archaeologists believe this warriorhero was still remembered and venerated several decades after his death, as shown by the remains of a small wooden mausoleum built above his grave. That his tomb became a cult centre is suggested by the ritual exhumation of his skull via an oval hole dug in the earth, and by part-burned wood found close to his tomb, both of which remain clearly visible.

This small shrine grew in stature over the years, and eventually a larger building (which may have contained an altar or statue) was constructed above the grave. To argue for direct continuity between this early shrine and today’s cathedral might be too daring, but is it possible that the tomb of this ancient Celt made a significant contribution to Geneva’s later urban development?

Medieval montage

My tour ended at ‘the south cathedral’, developed between the 5th and 10th centuries AD to educate the faithful via the teaching of sacred texts. On my way to the exit, I was treated to one last late-antique splendour: a beautiful floor mosaic in the 5th-century bishops’ reception room, which stood adjacent to the south cathedral and opened onto its choir. Such exquisite mosaic detailing is rare north of the Alps, and both the design and the pavement’s under-floor heating reflect the power and importance of Geneva’s early medieval bishops.

As time wore on, the north and south cathedrals gradually fell out of use, supplanted by the expanding east cathedral, to which a large Romanesque crypt was added at the turn of the millennium. This monster cathedral underwent further gradual transformation and extension over the next few centuries, its character changing dramatically after Reformation. What remains today is a hybrid of architectural traditions and religious influences – a building with a rich and multifaceted story to tell.

The archaeologists who excavated this site must be congratulated for their efforts in the mammoth task of unpacking this huge, tripartite structure, the history and archaeology of which has been recovered, preserved, and presented with the utmost skill and sophistication. This is the way to do it, and a vast underground cavern of ancient and medieval treasures awaits those dedicated enough to sacrifice an afternoon by the lake in favour of navigating this magnificent mud-filled maze.

This article was published in CWA 83.  Read on in the magazine or click here to subscribe.

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