Limits of Empire

Further expansion was simply not in the cards.  Caesar’s conquest of Gaul was a tour de force which required every ounce of his military genius and came close to disaster on several occasions.  His feat could not be replicated in the gloomy forests of Germany, and economically attempting to bring civilization to Germania via the Eagles of the legions made no sense, and was probably militarily impossible in any case.  The Dacian campaigns of Emperor Trajan demonstrated the immense effort required to make further conquests into barbarian Europe and how little pay back for all of the expenditure of blood and treasure there was.  This cost benefit analysis safeguarded the bleak mountains and plains of  what is now Scotland from the tread of the Roman legions.  In North Africa the Sahara was an impenetrable desert.  Trade with the various Nubian kingdoms south of Egypt was much more profitable than direct rule would have been.  In the East the eternal bitter rivalry with the Parthians and later the Sassanids made all conquests fleeting.  Lacking the compass, and little enthusiasm for expansion overseas, the Roman empire had gone as far as it could go.  It is a tribute to Roman statesmanship and the fighting prowess of the legions that this ancient mega state held together as long as it did.