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University of Basel

Views of pre-medieval Basel

Peter-Andrew Schwarz

From the oppidum to the first cathedral: For anyone looking to reconstruct the Celtic, Roman and early medieval history of Basel, the starting point has to be archaeological discoveries such as walls and pits, along with finds like animal bones, coins and pottery vessels. Inscriptions and texts have an important – although still only complementary – role to play.

Castrum auf dem Münsterhügel und munimentum in Kleinbasel (um 380 n. Chr.) [Bild: Archäologische Bodenforschung Basel-Stadt].
Castrum on the cathedral hill and munimentum in Kleinbasel (around 380 AD). © Archäologische Bodenforschung Basel-Stadt

From written sources, we know that in the second century BC the bend in the Rhine and the southern part of the upper Rhine basin were inhabited by a Celtic population, termed Raurici by Caesar and other classical authors. Their older, unfortified settlement (known as ‘Basel gas factory’ after the former site of the gasworks) was located on what is now the Novartis campus and dates from the period 150 to 80 BC. The uniform alignment of the buildings and the presence of ditches, thought to mark plot boundaries, suggest that the settlement – which covers around 15 hectares – was laid out to a plan. One thing we can be sure of is that this large settlement, with its agricultural hinterland, anticipated a development that led to the modern city of Basel – in economic terms, too. Amphorae of wine from the Mediterranean, pottery from Bohemia and amber from the Baltic testify to the settlement’s role as a hub of long-distance Celtic trade.

The cathedral hill as a nucleus

Around 80 BC, the focus of the settlement shifted – probably for military and political reasons (pressure from Germanic tribes) – to the cathedral hill, the nucleus of the later city of Basel. This spur, protected by the steep banks of the Rhine and the river Birsig, was fortified around the Rittergasse by a murus gallicus, a reinforced earth wall, and a ditch. We see evidence of this even today in the local topography (on the Bäumleingasse). The oppidum (fortified settlement) was accessed via a gateway on what is today the Rittergasse. However, hardly anything is known about the oppidum’s internal layout. It is also unclear whether this was one of the approximately 400 settlements burned down and abandoned by the Helvetii, Boii, Tulingi and Raurici when they left the area in 58 BC.

Following Caesar’s defeat of the Helvetii at Bibracte in 58 BC, Rome decided for strategic reasons to forge an alliance (foedus) with the Raurici living on the bend in the Rhine. As foederati of Rome, they were responsible for protecting the frontier of the imperium Romanum, which at that time still ran along the Rhine. This was accompanied by the establishment of a second settlement in the region. In the summer of 44 AD, Lucius Munatius Plancus, one of Caesar’s generals, had founded the first Colonia Raurica; there is still some dispute about whether this was on the site of the later colony of Augusta Raurica (at Augst, in Baselland, and Kaiseraugst, in Aargau) or in the oppidum on the cathedral hill. One thing we can be sure of is that the cathedral hill continued to be occupied, whereas so far Augusta Raurica has yielded no finds from the time when the first colony was established. On the contrary, the current state of research even suggests that an existing Celtic settlement located within the perimeter of the later caput coloniae was abandoned during this period.

According to two bronze inscriptions discovered at Augusta Raurica, the second foundation of the colonia P[aterna] M[unatia Felix] Apollinaris Augusta Emerita Raurica – this time not just de iure but de facto – probably took place shortly after the occupation of what is now Switzerland during the so-called Alpine campaign (15 BC) by Lucius Octavius, a relative of Emperor Augustus. From this point onwards, it is likely that a Roman garrison was also stationed on the cathedral hill. It is still unclear whether this consisted of a larger unit or smaller detachments; where and how the soldiers were housed is another unresolved question.

In the shadow of Augusta Raurica

Following the garrison’s withdrawal in the mid-first century AD, the murus gallicus was razed and the fortification ditch partly filled in. The Roman civilian settlement (vicus) moved to the area south-east of the cathedral hill. Although this vicus sine nomine (Arialbinnum?) had a certain economic importance, thanks to its position on an important trunk road and its quayside where the Birsig joins the Rhine, throughout the heyday of the imperium Romanum (from the first to the third century) it was overshadowed by the colony of Augusta Raurica 15 kilometers further upstream. This enjoyed some key advantages as a location, such as its position at an important crossroads. After abandoning the upper German-Rhaetian limes, the Romans moved the frontier back to the rivers, which were easier to defend. From 260 onwards, the Rhine, the Danube and the Iller formed the ‘wet’ frontier between the imperium Romanum and the Germanic tribes (the Alemanni, the Juthungi and the Franks). The settlement on the approaches to the cathedral hill was abandoned and the strategically important cathedral hill was fortified once again (see image above).

Furthermore, in his res gestae, the Roman officer and historian Ammianus Marcellinus reports that in 374 AD Emperor Valentinian I (364–375) had a fortification (munimentum) constructed in Basilia. He indicates explicitly that the town acquired the name Basilia only after Valentinian I’s stay there, having previously been called Robur by the locals. According to the Notitia Galliarum (390–413), the civitas Basiliensium was significant primarily as a civilian center, by contrast to Castrum Rauracense (Kaiseraugst), whose importance was mainly military and ecclesiastical. Around 343/346 AD, Iustinianus Rauricorum, the first bishop for our area who is known by name, resided in Castrum Rauracense.

During the transition from late antiquity to the early Middle Ages, from the fifth century onwards, we have evidence of three peoples on the bend in the Rhine, who for the time being were still living as separate groups: Romancespeakers (descendants of the Gallo-Roman provincial population); and Alemanni and Franks, two Germanic peoples. In the fifth and sixth centuries, the Rhine formed a linguistic and cultural boundary between the Romance-speakers living in the castrum on the cathedral hill and the Alemannic settlements in ‘Kleinbasel’. Later, this took on the role of a diocesan boundary, with Grossbasel forming part of the archdiocese of Besançon and Kleinbasel falling within the diocese of Constance.

Under Frankish rule

From the fifth to eighth century, new villages, hamlets and farmhouses were established around the castrum on the cathedral hill (place names ending in ‘-ingen’ such as Gundeldingen, Kleinhüningen, Binningen and Bottmingen). This ‘decentralization’ was the result of changes in political organization following the withdrawal of Roman frontier troops around 400 AD and the collapse of the provincial administration in the first half of the fifth century. Other important factors were the decline of trade and industry and the growing importance of agriculture. Construction techniques also testify to the ‘ruralization’ of society, with wood replacing stone as the preferred material for farm buildings and houses.

In 496 AD, the Frankish king and founder of the Merovingian monarchy, Clovis (466–511), subjugated the Alemanni. The area around Basel became part of the Frankish empire, which also included large parts of France and Belgium. We find archaeological evidence of the Franks’ arrival in, for example, the cemetery of ‘Basel-Bernerring’. The Frankish central government’s restoration of the Roman trunk road to central Switzerland, through the Birs valley and across the petra pertusa (Pierre Pertuis pass), was a key factor in ensuring that Basel – not Augusta Raurica – became the main regional hub during the early Middle Ages. Basel’s increasing economic and political importance in the first half of the seventh century is confirmed by Merovingian gold coins. These were struck by a Frankish monetarius (master of the mint) named Gunso and carry the circular inscription Basilia fit – made in Basel.

Construction of a round-tower cathedral

Between late antiquity and the reign of Charlemagne (771– 814), the lingua franca, Latin, was gradually replaced by Alemannic dialects; the personal names that appear in documents from the Carolingian period onwards are almost exclusively ‘German’. From the seventh century, Germanic immigrants founded more villages and hamlets in the surrounding area – place names ending in ‘-wil’ such as Oberwil, Therwil and Reigoldswil. However, the names of settlements that had been founded by the Romans and continued to be inhabited by Romance-speakers, such as Munzach, Dornach and Solothurn (place names ending in ‘-acum’- und ‘-durum’) – have survived down to the present day. In the early seventh century, there is also evidence of the presence once again of high-ranking church dignitaries. Around 615 AD, a Ragnacharius is mentioned in a document as the praesul (overseer) of the churches of Augst and Basel. It is unclear whether an independent bishopric was (again) in existence at this time, as we have a reliable list of bishops only for the period from the late eighth century onwards.

Eventually, Basel’s political importance (for the church) was boosted by the appointment of Haito (762–836), abbot of the monastery of Reichenau, as its bishop. Haito (also called Heito or Hetto) was a member of the Frankish Carolingian elite and a close friend and confidant of Charlemagne; he also witnessed Charlemagne’s will. After taking office, Bishop Haito had a new church erected to replace the one that had existed previously, which had clearly fallen into disrepair. This is probably identical with the round-tower cathedral for which archaeological evidence survives – the predecessor of the predecessor of today’s cathedral (see image above). Graves dating from between the 8th and the 12th centuries show that the cathedral hill was (also) used as a cemetery. Whether we are dealing with a number of smaller cemeteries from different periods or burial places for particular (privileged?) groups of people is still an unresolved question.

Professor Peter-Andrew Schwarz holds the Vindonissa Chair in the Department of Classics at the University of Basel.

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