The Middle Ages
It's a shame we don't call them “The Dark Ages” anymore, because “how middle were they?” jokes just don't have the same ring to them. See, turns out the “dark ages” weren't all that dark, what with all those non-white people making significant cultural and intellectual advancements during the Middle Ages. And it turns out it wasn't all that “good to be da king,” despite what Mel Brooks promised us. Oh and Medieval food was mushy and plain.
Gee, if nothing was like we pictured, did the Middle Ages even happen? Yes, of course they did. We know because of all the dong-based coats of arms. Which, seriously guys. Coats of arms are so silly. We're talking less “flayed man” and more “blindfolded cheetah.” God bless whatever forgotten-to-history goofball thought that one up.