In effect, those were the borders of the known world to the Romans. A world which they had conquered. On coins, decrees, monuments, they portrayed the theme “restitutor orbis”, whenever an Emperor managed to restore peace to the world. read more
Heck, if all those barbarians had just stopped fighting each other, they could have pushed the Romans back. Julius Caesar conquered Gaul with a numerically inferior fighting force because of training and tactics, not military might. read more
No cities to conquer, the first German cities were actually founded by the Romans, like e.g. Aachen, Cologne or Trier. The Germans were primitive tribesmen and had little to offer to the Roman Empire. read more