The "Dark Ages", or at least the Protestant version of the Dark Ages. First, I am not a medieval scholar or a Church scholar or a historian of any kind. I've never touched a primary source. I'm a big fan of the period, though, so I'll try and elaborate. The Renaissance, the name for the time period following the "dark ages", was this explosion of new learning. New ideas and ways of thinking abounded, along with a sort of scoffing about old practices. Think about how quaint we think people from 1910 are with their cute suits and Spanish Flu. Now remember that not only during the Renaissance are these times-a-changin, but that we've gone from a predominantly Catholic society during the medieval period to a predominantly (sort of) Protestant one. Protestants don't like the Catholic Church, and now the learned aren't just Church Scholars; in fact they're the minority. So now we have all of these learned men who not only see the last 500 years as backwards and barbaric, but they also have a personal distaste for The Church, who has been ruling everything for centuries. So what do you write about when cataloging the last half millennia? Why, the oppression of the Catholic Church on learning, of course! If you're at all interested in this topic, I highly recommend Thomas F Madden's lecture series on the Medieval World, Parts I and II. Hell, any of his lectures are awesome.