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Dark Ages vs. Middle Ages

Dark Ages

noun

the period in European history from about a.d. 476 to about 1000.
the whole of the Middle Ages, from about a.d. 476 to the Renaissance.
(often lowercase) a period or stage marked by repressiveness, a lack of enlightenment or advanced knowledge, etc.

Middle Ages

plural noun

the time in European history between classical antiquity and the Italian Renaissance (from about 500 a.d. to about 1350): sometimes restricted to the later part of this period (after 1100) and sometimes extended to 1450 or 1500.