You seem to be well educated, so maybe you can clear up some miss information for me. I thought the general thought the Roman Empire continued for much longer, but through the Catholic Church. The control of other countries that is. Perhaps you could endulge. thanks.
I recommend the novel ”Count Belisarius” by Robert Graves - a fascinating account of that period, the religion and the politics.
http://www.amazon.com/Lost-West-Forgotten-Byzantine-Civilization/dp/0307407969
This should help you out - you will probably see it in your local library.