In Hilary Mantel's famous historical fiction Wolf Hall, she implies more than once that the court fools of figures in the era of Henry VIII often had some form of learning difficulty. Indeed in one passage, she suggests that fools were often taken in by nobles as a way of protecting and providing employment for disadvantaged members of the community.
Here's an example concerning Henry Pattinson, a fool employed by Thomas More:
The man is a great brawler; normally you take in a fool to protect him, but in Pattinson’s case it’s the rest of the world needs protection. Is he really simple? There’s something sly in More, he enjoys embarrassing people; it would be like him to have a fool that wasn’t.
This contrasts strongly with the picture given in Wikipedia and other online sources, which posits fools as well-trained professional entertainers.
Mantel seems to be very well researched in considerable detail on many other aspects of the history she portrays. But her portrayal of fools is a total mismatch with anything I can find on the subject. Is there any accuracy to it?