>>34609
Chris Wickham has a book or two on the transition from late antiquity to early medieval in Europe and the Middle East that covers a lot of ground. Henri Pirenne's Medieval Cities is somewhat outdated, but it's still a fantastic read for some insight into the early and high medieval city and how it differed from Roman urbanization. If you've got the time Fernand Braudel has several volumes on the Mediterranean and early capitalism stretching from antiquity to the early modern period.
As for defines or really distinguishes a civilization, going philosophical seems to me a vague landscape and not very consistent even within a single culture over any length of time. There are moments when what is normally considered Western European culture embraced philosophy that did not differentiate between mankind and his universe, and especially times when God was very much in tune with the suffering of mankind. Conversely, there are times when non-Western civilization has also shared similar outlooks especially when influenced by Hellenism, such as Islam.
What you're really describing then isn't Western Civilization, but Hellenic Western Eurasia, a region whose cultural traffic and economy are ultimately dominated or powered by the Mediterranean. While somewhat contiguous with the Roman Empire at its height, this region extends further into Northern and Eastern Europe as well as the Sudan and the Red Sea. It's not a civilization, but more like several different civilizations bumping shoulders.
So instead, I suggest defining Western Civilization by more concrete things such as language and script, a common literature and education, ease of movement and relocation within its borders, and common legal and political institutions. Thus:
>Carolingian script and vulgar Latin
>Quadrivium/Trivium liberal education
>Normally free movement of clergy and merchants
>Frankish-style aristocracy, free cities, and Canon/crown law codes
Would distinguish what would be Western Civilization from, say, Islamic Civilization though the two both influenced each other and were influenced by Rome and Greece.