The Limes used either a natural boundary such as a river or typically an earth bank and ditch with a wooden palisade and watchtowers at intervals.
In the Roman limites we have, for the first time in European history, clearly defined territorial borders of a sovereign state that were visible on the ground to friend and foe alike.
Most of the Upper German-Rhaetian Limes did not follow rivers or mountain ranges, which would have formed natural boundaries for the Roman Empire.
The latest research tends to view at least the Upper Germanic-Rhaetian Limes not as a primarily military demarcation line, but rather a monitored economic boundary for the non-Roman lands.
Only after the foundation of the German Empire could archaeologists begin to study more precisely the route of the limes, about which there had previously only been a rudimentary knowledge.
In 1892, the Imperial Limes Commission (RLK) was established for this purpose in Berlin, under the direction of the ancient historian, Theodor Mommsen.
This division followed the administrative boundaries in 19th-century Germany and not that of ancient Rome: Upper Germanic-Rhaetian Limes in general Sections