- Feb 2014
- Colonia Valensiana
I am afraid that I cannot find a primary source but I have read that in M. Carroll, Romans, Celts and Germans: The German Provinces of Rome.
Digital Atlas of the Roman Empire
What I can recall is that the Constantine erected some fortifications across the Rhine in the IV century, if I am right.
Here's what I could find on a prominent site in the area but it's in German.
Vicus Aurelianus. Das römische Öhringen - Archäologische Informationen aus Baden-Württemberg - Gesellschaft für Archäologie in Württemberg und Hohenzollern e.V.
VICUS AURELIANUS - Aqueducts - Roman Aqueducts
There was a Roman presence beyond the Rhine that's beyond any doubt but we can't be sure about its true character.