I think some of these misconceptions appear in popular media predating the reenactment scene. Mark Twain in particular is guilty of it. Connecticut Yankee has

I think some of these misconceptions appear in popular media predating the reenactment scene. Mark Twain in particular is guilty of it. Connecticut Yankee has a bunch of stuff like knights needing cranes to get on their horses and whatnot. The whole book is about how crude and simple minded medieval people were.