Editing Portage (section)

====Pre-Viking and Viking era northern Germany====
The Skagerak always has been treacherous for shipping and early navigators tried to avoid it. There are various river systems in (modern) northern Germany and southern Denmark where the watershed is narrow and low, such as between the Treene (discharging into the North Sea) and the Schlei (discharging into the Baltic) that would have allowed portage. There is no certain physical or written evidence, except that it is known that goods were transported along these routes between different merchant settlements.