: Quite frankly, the Dark Ages are labelled as such because they are 'dark' for us as historians. Since only clergy and noble families were adequately educated, much of the history of the time is NOT recorded for us to review.
Some teachers will say it's because learning, ie. reading & writing were at a historic low, so the people were dumb, etc., but it's more correct to refer to the fact that WE as modern historians know very little of the entire period. Because the Catholic Church held such sway over what was written, copied, translated, and recorded, anything they found to contradict their view(s) of the world often went unrecorded.
Hope it helps!