From the late 2nd century onwards, the Roman Empire was weakened by Germanic incursions, civil wars and plagues. The economy deteriorated and the population became impoverished. After the fall of the limes around AD 260, the frontier of the empire was moved back to the Rhine. The town was once again located on the border. The times were unsettled with constant fighting. Around AD 280, the outcrop of the Kastelen, the area above the present-day museum, was fortified by a wall with a bank and ditch enclosure. The fortification provided shelter to the already badly decimated population of Augusta Raurica. The other quarters of the town were largely abandoned.