Celtic Basel: the Gasfabrik settlement and the oppidum on the Münsterhügel

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The earliest traces of a substantial settlement on the site of Basel date from the late Iron Age, the period of the La Tène culture. In 1911, during the construction of a gasworks in the north of the city, workers uncovered the remains of an extensive open settlement on the left bank of the Rhine, which archaeologists have since called Basel-Gasfabrik. The settlement, occupied roughly from the second half of the second century BC to the early first century BC, covered some fifteen hectares and appears to have been a centre of craft production and trade.¹

The finds at Basel-Gasfabrik are instructive for a book on a financial centre. They include imported amphorae from Italy, which contained wine and prove that the settlement was connected to the Mediterranean trade that reached Gaul through the Rhône and the Saône and came to the Rhine through the Burgundian Gate. They include Celtic coins, among them cast potin coins and struck silver and gold coins, which show that the inhabitants used money in a form that went beyond mere prestige gifts. And they include traces of glass, metal and ceramic workshops that produced for more than local needs.² Some two thousand years before the first bank was founded in Basel, the site was already a place where goods from distant regions were exchanged and where money circulated.

When the open settlement was abandoned around 80 BC, the population appears to have moved to the Münsterhügel, where a fortified settlement, an oppidum, was built. Its rampart, a murus gallicus of timber, earth and stone typical of the late Celtic fortifications of Gaul, cut off the spur from the plateau to the south. Remains of the rampart were excavated at the Rittergasse, where a section has been made visible in the archaeological information point below the street.³ The move from an open settlement to a fortified hill reflects the insecurity of the period, in which Germanic groups crossed the Rhine and the Celtic peoples of the region were under pressure.

The population of the region belonged to the Rauraci, a Celtic people whom Caesar mentions in his account of the Gallic War. According to Caesar, the Rauraci joined the Helvetii in their attempted emigration to south-western Gaul in 58 BC, which Caesar stopped at Bibracte.⁴ After their defeat, the survivors were sent back to their territories, which became part of the Roman sphere of influence. The Rauraci would give their name to the Roman colony founded in their territory: Augusta Raurica.

The Celtic period left three legacies that are relevant here. The first is the use of the site as a centre of exchange at the meeting point of long-distance routes. The second is the Münsterhügel as the political and religious centre, a role that it retained in the Roman fort, in the episcopal city and until today. The third is the name of the people, which survived in the name of the colony and later of the diocese, the episcopatus Rauracensis or Basiliensis, and which the canton of Jura still invokes in its heraldic and cultural traditions, as the former territory of the Prince-Bishopric of Basel.

Notes

1. On Basel-Gasfabrik, discovered in 1911 during the construction of the gasworks at Voltastrasse, see HLS, article "Basel-Gasfabrik"; the publications of the Archäologische Bodenforschung Basel-Stadt. Dates and surface to be verified. ↩
2. Coin finds at Basel-Gasfabrik, including potin coins and imports, are discussed in the numismatic literature on the Rauraci; see HLS, article "Rauriker"; for the Mediterranean amphorae, the reports of the Archäologische Bodenforschung Basel-Stadt. ↩
3. On the oppidum on the Münsterhügel and the murus gallicus at the Rittergasse, see HLS, article "Basel (Gemeinde)", section on prehistory and antiquity; Archäologische Bodenforschung Basel-Stadt, information on the Murus Gallicus site. ↩
4. Caesar, De bello Gallico I.5 (the Rauraci join the Helvetii) and I.29 (figures on the emigrants recorded in the Helvetian lists). The historicity of Caesar's figures is disputed in the literature. ↩

For general information only. This article does not constitute legal or tax advice, does not replace advice on an individual case and creates no lawyer-client relationship. It reflects the legal position as of September 2025.