Archaeologists have unearthed the remains of a 4th century AD amphitheatre in the Roman city of Augusta Raurica, situated on the banks of the Rhine near the village of Kaiseraugst, Switzerland.
It was revealed in December 2021 during excavations of an abandoned Roman quarry where the construction of a new boathouse for the Basel Rowing Club is scheduled. The work was undertaken by Aargau Cantonal Archaeology.
The amphitheatre was once formed of an oval ring of walls measuring 50 metres long and 40 metres wide. A large gate flanked by two adjacent entrances were built on the south side of the complex, and along the western perimeter several entrances with thresholds constructed from sandstone blocks were identified.
The arena had been fitted with wooden grandstands – as evidenced by remains of post holes – and the interior walls were plastered.
Dating back to the Late Antiquity (c. 4th century AD), the amphitheatre is possibly the youngest such monument to be discovered across the Roman Empire.
It is the second amphitheatre unearthed in the canton of Aargau – the other being that in the Roman town of Vindonissa, now known as Windisch – and the third in Augusta Raurica.
Founded in 44 BC by Lucius Munatius Plancus and named after the local Gallic tribe, the Rauraci, the city of Augusta Raurica is the oldest known Roman colony on the Rhine. During the 2nd century AD, it was a booming commercial centre; the archaeological remains of its numerous amenities, including public baths, temples, and an aqueduct, can be explored by visitors.
This latest discovery is located immediately west of the city’s fortress, the Castrum Rauracense.
According to a statement by the Aargau Cantonal Archaeology, the castrum ‘was an important settlement with a military function on the Roman border, but also an administrative centre’.
Steps will now be taken to preserve and protect the amphitheatre in situ.