When looking at this period of history, from the perspective of the record-keeping at the time, there are some things that should be kept in mind.
The rate of literacy plummeted.
Technology, including paper making, retreated.
Paper was not widely produced.
Few, if any places in Continental Europe, went more than half a generation without a major war.
There were migrations of whole peoples, including Huns, Goths, Visigoths, Vandals, and Aryans. These people either displaced those already there or were assimilated.
In short, there was much upheaval, political, social and physical.
But this really only affected continental Europe. Africa, the Moslem world, India, China, etc. These places did not experience a “Dark Age” during that time.