<span>It was "Charlemagne" who was the Frankish leader who reestablished the ancient culture of the Mediterranean world in Western Europe and was known as the "light of the dark ages," due primarily to his economic and political reforms. </span>
A.Charlemagne <span>Charlemagne was a Frankish leader who reestablished the ancient culture of the Mediterranean world in Western Europe and was known as the "light of the dark ages."</span>
Enemies usually refer to bad guys. So if it is a "common enemy" then it is a common bad guy that everyone knows about. It can also mean that you and someone else share an enemy, but that is stilll negative.