Taking advantage
Basically, what Sir Boss does is what politicians and others have been doing for ages. He takes advantage of the ignorance of the populace. As a result, he looks to be all knowing and powerful as their fear intensifies. Obviously, in the days of King Arthur, people didn't have easy access to a lot of information.
They also wouldn't have had the time or the inclination to educate themselves. Today, there really isn't any excuse for ignorance; at least not to the extent that some people are ignorant and misinformed. Most of us have, at our fingertips, access to all the information in the world yet many fail to take advantage of it.
Woman, man! That's the way it should be Tarzan. [Tarzan and his mate]