Why is it incorrect to refer to the Middle ages as the Dark ages?

The expression 'Dark Ages' relates to the period c. 450-750 (or slightly later) in Western and Northern Europe. It is called by this name because there are very few written records of events from this time, and as a result modern knowledge of this period is rather limited. However in Byzantium, Roman civilization continued in this period and there are plenty of written records. In recent decades professional historians have tended to avoid the term as it is often taken to mean that all kinds of terrible things happened then. From about 800 onwards literacy, architecture and the arts revived and expanded - and led into the Middle Ages. Please note that the dates given are very approximate.