Rhine, Danube and for part of the time, Euphrates.
irdk
The natural borders in the northern parts of the Roman empire in what can be called "central Europe" were the Rhine and Danube rivers. Incursions by Germanic Tribes for example were an ongoing problem for Rome. In the ending years of the empire, these river boundaries were crossed en mass by barbarians.
River Meuse
The Roman empire almost totally surrounded the Mediterranean Sea.
Both the Tigris and the Euphrates are in the eastern part of the Roman Empire.
The Roman empire surrounded the Mediterranean Sea.
jerusalem, palestine and syria.
It probably got too big to defend its borders.
Danube River
Danube River
Danube River
The stationed the bulk of the Roman legions in the frontier provinces of the empire.
The stationed the bulk of the Roman legions in the frontier provinces of the empire.