Ad Fines (Vinxtbach)

In the summer of 58 BCE, Julius Caesar was the first Roman general to reach the river Rhine, which he accepted as the eastern frontier of his theater of operations, Gaul. Some forty years later, the emperor Augustus reorganized the Rhine frontier, which was from now on guarded by two armies: the army of Germania Superior (= the Middle Rhine) and the army of Germania Inferior (= the Lower Rhine). Roman attempts to conquer the country east of the river were checked by the Germanic tribes in the famous battle in the Teutoburg Forest in 9 CE.

The small Vinxtbach, which empties itself in the Rhine just south of modern Bad Breisig, marks the boundary between the occupation zones of the two Roman armies. When the emperor Domitian converted these military sectors into real provinces (in 83 or 84 CE), the Vinxtbach was to be the border. Near the Rhine was a small settlement, called Ad fines ("near the border"). On the opposite bank was the small limes castle of Rheinbrohl.

It is not a logical boundary. Just six kilometers to the north is the rugged valley of another stream, the Ahr, which is a much more impressive landmark. It has been argued that the Vinxtbach was the northern border of the area of the tribe of the Treveri, but this is merely transferring the question from history to prehistory. The ancient name of the little river appears to have been Obrincas.^note[Ptolemy, Geography 2.8.]

It remains a boundary to the present day. For centuries, the Vinxtbach has been the frontier between the archbishopric of Cologne and Koblenz. Today, it is still considered to mark the southern boundary of "Kölsch", the dialect spoken in the area between Cologne and Venlo. This area was not affected by the High German consonant shift, a process of linguistic change in southern Germany that started in the Late Roman period. In the south, modern German was to come into being, whereas the Saxons of the north, who settled in Britain, and the Franks, who settled in the Netherlands, took an old Germanic dialect with them.

We can say that the Vinxtbach is the boundary between proto-English and proto-German.