[Right_Wing_Madman]

After much conflict with the Germans during his reign, Augustus Ceasar seriously considered a full-scale invasion of Germania, but he didn't like the resulting border if he was successful. The Romans would then have to defend a long flatland frontier against the Slavs to the east. So he decided that the Rhine River would be the border against Germany and he fortified it. After 2,000 years and numerous wars, the Rhine remains the dividing line between Roman and Germanic civilizations.

[SunkenCiv]

The notion that the Rhine remained the border has been superseded by evidence. There's an anachronistic nationalistic urge that really picked up steam in the mid 19th century, in Germany, Scotland, Britain, France, etc to invent "resistance" to "occupation" but it's merely quaint now. When Diocletian re-established a unified empire, he nevertheless split it into four parts, and the western/northern area had its capital in what's now Trier. The city of Cologne got its name from "Colonia Claudia Ara Agrippinensium". Traces of Roman camps and such have been id'ed a good bit farther east in recent years.

• Report: Ancient Roman graveyard found in suburban Copenhagen [10/11/2007]
• Roman Baltic [kw]