Was it literally dark in the "dark ages? " i have heard it said that there was a volcanic eruption that darkened the sky for many years.? any truth to that? (i know it preceded the "age of enlightenment" etc.)

Well no the "dark ages" were not dark because of volcanic ash . It was just a very depressing time period with the bubonic plague and all. Although I do think you probably overheard someone talking about Pompeii I guess? Since thats the only thing that comes to mind to me about a violent volcano eruption.

Cpopulation density

Africans learned what the europeans wanted them to learn. instead of learning about african history and current information that could and would them they learned solely what europe wanted them to. and not everyone received the same education, some received better and others none.