[Someone]

> The Danube and the Rhine were the two major rivers that could be navigated by Romans and they were the borders of the empire for that reason: they were the only way to supply border garrisons efficiently

I don’t see why the southern shore of the river would be easier to keep supplied from those rivers than the northern one. So, if the empire ended there because of supply issues, wouldn’t it end a short distance north of the river?

Also, wouldn’t those rivers only help supply from other border areas, not from the much larger inner parts of the empire?

I would think those rivers just are natural boundaries because they provide some protection against invading enemies.

[thrown_22]

>I don’t see why the southern shore of the river would be easier to keep supplied from those rivers than the northern one. So, if the empire ended there because of supply issues, wouldn’t it end a short distance north of the river?

Retreat is easier when not drowning.