Hadrian's Wall in Britain
the Danube River in Continental Europe
roman sa
Most of the northern borders of the empire in Europe were marked by the rivers Rhine and Danube. Dacia (Romania) was a Roman province beyond the Danube, but it was also given up by Aurelian between 271 and 275 due to continuous attacks from outside . The Romans had lands beyond the Rhine in Germany, but they were given up in 340-341 by Constans for the same reasons. Thus, eventually these two rivers became the whole of the northern frontier. The source of the Danube is close to the Rhine The above only takes continental Europe into consideration. However the Roman empire extended much further north into Scotland. There were rivers there and the Romans had marching camps as far north a the Firth of Clyde and the Clyde river and even further up to the Amrick river.
The northern border of the Roman province of Britannia was Hadrian's Wall.
mediterranean sea
He controlled the Roman border by being a very harsh emperor and learning as he went along. One of his "border achievements" was the building of Hadrian's wall in northern Britain in order to stop border raids.
Hadrian's Wall in Britain the Danube River in Continental Europe
I assume it's because the former emperor Augustus died and the other emperor was content with the border.
Hadrian's Wall, the Rhine River, and the Danube River
Hadrian's Wall was a wall which marked the border of the Roman Empire in northern England. It is named after the emperor Hadrian, who commissioned its construction.
He controlled the Roman border by being a very harsh emperor and learning as he went along. One of his "border achievements" was the building of Hadrian's wall in northern Britain in order to stop border raids.
The Holy Roman Empire
The southernmost border was the one between southern Egypt ad Numidia