You can't "prove" it was a strong empire, but you can provide evidence. As you can see below, just some points that will make it evident.
Explanation:
"<em>The Roman Empire, among the most well known in the ancient world, lasted for nearly a thousand years. Conquering peoples of the Greek Peninsula, countless Britannic Tribes, and overthrowing the great Carthaginians are among a few of the incredible accolades of the Romans. Of course, this could not have been done without the mighty Roman Army which evolved over centuries of trials and error. The Roman Army was feared not only because of its technological advantage over others, but because of its intense discipline and flexibility. It was this aspect of the Romans that made their "Legions" a force to be reckon with. For this reason alone, one might argue that the Roman's had one of the strongest Empires at the time of their existence." </em>
