The area around Rheinfelden was already settled about 10,000 years ago. At that time, people lived in the "Hermitage", a small natural cave next to the current highway. In the year 45 BC, a few kilometers west, the village Augusta Raurica was made, the first Roman town in Switzerland, near modern Kaiseraugst. Towards the end of the 4th century, a fort was built at the western settlement.