1. – After the fall of Rome itself in the late 5th Century, the “development” of Europe came to a relative halt (if not utter regression), lasting for some generations. Traditionalist history asserts (perhaps erroneously) that this “dark age” lasted until the Renaissance and the rebirth of classical (Greek and Roman) culture.
2. – The Byzantine Empire took up the Roman mantle, continuing the influence of the Empire for nearly a millennium.
3. – Western Europe was carved up into a vast number of small, locally-controlled Christian states, led by primarily Germanic tribes, which would ultimately give rise to the Feudal System that would dominate the Medieval period.
4. – The influence of Islam during the 7th century moved rapidly to fill the vacuum left by the by-then-complete dissolution of Roman structure, with much of the Mediterranean world including Greece, the Balkans, southern Italy, the northern African states, most of Spain, southern France, and more coming under Muslim rule, an expansion which would not formally end in the west until the rise of the Carolingian Empire (or rather its two catholic children, the Holy Roman Empire and the Kingdom of France). This assumes a total look at Roman influence and includes the slow decline of the Byzantine Empire in its ability to hold back Turkish enterprise (by which it was eventually consumed in the early 15th century).
Actually the Turks didnt take the balkens until the late 1450’s after they were finanlly able to defeat the Eastern Roman Empire. Yes i said it they wers not call the Byzantine Empire until many years after the fall of Constantinople even then is wasnt in a good way as the term had took on a new meaning deceitfull little Greeks.