Assignment:
Despite shifts in authority, ethnic composition, and religion from 400 to 600, Roman society in western Europe continued to exist. Discuss the features of Roman culture that were preserved and those that were lost. Discuss either Islamic or Byzantine Civilization in the Early Middle Ages. How does Charlemagne fit into the creation of Europe?
If you want to say more, how about this--Discuss the concerns of monks and how monasteries provided benefits to surrounding communities.
For your information:
In terms of dating purposes I've always seen the Crusades (late 11th century) as a convenient end point of the "Early Middle Ages" and the beginning of the "High Middle Ages". Although I admit that not every Medievalist would agree to this dating scheme. The Crusading movement is a good way to also gain insight into the Western Europe's interaction and relationship with the Byzantine Empire and the Islamic Caliphates. Interestingly, certain scholars have seen it as the last great Barbarian invasion, an early expression of European expansion, or a reconquest of lands that had once been part of the Roman empire.