The Upper Germanic Limes, also called Rhaetian Limes or simply "the Limes", was the border between the Roman Empire and the unsubdued Germanic peoples.
The Limes extended from Koblenz on the Rhine to Eining (close to Kelheim) on the Danube. The total length was 568 km. It included at least 60 castles and 900 watchtowers.
The first emperor who began to build fortifications along the border was Augustus, shortly after the devastating Roman defeat in the Battle of the Teutoburg Forest in 9 A.D.. Originally there were numerous Limes walls, which were then connected to form the Upper Germanic Limes along the Rhine and the Rhaetian Limes along the Danube. Later these two walls were linked to form a common borderline.
The Limes was not an insurmountable bulwark. There were numerous apertures in order to enable trade between Romans and Germanic tribes.
Germanic invasions in the late 3rd century led to the abandonment of the Limes.
The Limes Germanicus (Latin for Germanic frontier) was a remarkable line of frontier (limes) forts that bounded the ancient Roman provinces of Germania Superior and Raetia, and divided the Roman Empire and the unsubdued Germanic tribes, from the years 83 to 260.
At its height, the limes stretched from near Bonn on the Rhine to near Regensburg on the Danube.
Germanic invasions in the late 3rd century led to the abandonment of the so-called "Obergermanisch-Rätischer-Limes" in favour of a Roman defense line along the rivers Rhine, Iller and Danube (Donau-Iller-Rhine-Limes) with watch towers in sight contact and heavily fortified castra at important trespasses (e.g.
A mediaeval limes is the Limes Saxoniae in Holstein
The stem of limes: limit-, which can be seen in the genitive case, limitis, marks it as the ancestor of an entire group of important words in many languages; for example, English limit and eliminate, "remove over the border." Modern languages have multiplied its abstract formulations.
In Pokorny Latin limen, "threshold", is related to limes, being the stone over which one enters or leaves the house, and some have gone so far as to view the frontier as a threshold.