Frontiers of the Roman Empire – The Lower German Limes. Riverine landscape near Xanten. The site of the double-legionary fortress of Xanten-Fürstenberg (centre right) situated today on the left bank of a now abandoned river course of medieval date (right), todays course of the Rhine (top right corner), the modern-day village of Xanten (top left corner) and Xanten-CUT (far top left corner).