Being a comedian as well as an historian, Terry Jones takes an established belief, turns that around, and presents proof for his assertion. For example, peasants did not live in complete squalor, owning some valuable property. Also class divisions were not as severe as thought; there are cases of low-born people who rise to quite high positions.
In the episode on kings, he says, “History isn’t necessarily what happened. It’s often what people want us to think happened.”