[ValenB4]

Just how did Mohammed roll back the Dark Ages? Mohammed was a nut. The desert Arabs did become the new leadership elite, much to the world's detriment. Sassanian Persia and the Byzantine Empire were quite capable of keeping civilization on its feet. Islam took over both of those areas and they have never recovered. But don't argue with me, I'm sure Ali Sina at www.faithfreedom.org would be quite interested in your point of view.

[muawiyah]

The Arab Islamic Empire NEVER took over Byzantium which limped along in an ever more progressive state of weakness until the Ottoman Turks finally conquered it in the 14th Century. That's nearly 700 years AFTER Mohammad.

Of course, in the meantime the Venetians had conquered Byzantium (circa 1000 AD), but they didn't keep it since it was such a wretched place.

Notice, too, that Venice began operations in a serious vein AFTER the start of the Dark Ages in 538 AD.

Japan also started to develop high civilization at the beginning of the Dark Ages.

If you want to read serious history of the 6th, 7th and 8th centuries AD, you will be limited to Japan, the Arabs, and Venice. Otherwise you are reading speculation since most of the world was a real mess in that period.

BTW, Muawiyah took over the Arab Empire and hired in many capable folks from Byzantium to run it for him. It was a clever move, and his new employees were happy for the work.