1 One reason why the Middle Ages are often called the Dark Ages is because, historians don't know as much about this time. In some ways, this period of time has been lost to history. Many important records from this time have not survived.
2 Not many people knew how to read or write. It could also be because of the near total loss of classical knowledge that had been gathered by the Greeks and Romans. This was lost to Europeans, but the Muslim world managed to keep hold of it and it was party through them that classic texts and knowledge were finally passed back to Europe.
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