[muawiyah]

You are overlooking the impact of the event that brought about the Dark Ages ~ 500 years in Western Europe and 300 years in China.

The Arabs in Arabia recovered first. They became the great engine of the economic transformation that lifted the Middle East out of the Dark Ages.

[Cronos]

The Arabs in Arabia recovered first. They became the great engine of the economic transformation that lifted the Middle East out of the Dark Ages.

Well, No. The Western Roman Empire collapsed in the 5th century, but the Eastern still survived and was the economic engine for the Mediterranean while the Persians did the same in Persia and North-Western India. The Muslims didn't come on the scene until the 7th century and they merely took over the workings of these two empires